Troubleshooting broken package page ask me to send this output from a series of

 ot@Danny1:/home/nolan# sudo grep -R proxy /etc/apt/*
root@Danny1:/home/nolan# echo $http_proxy

root@Danny1:/home/nolan# echo $ftp_proxy

root@Danny1:/home/nolan# grep proxy /etc/bash.bashrc
root@Danny1:/home/nolan# sudo fuser -vvv /var/lib/dpkg/lock
root@Danny1:/home/nolan# cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=10.04
DISTRIB_CODENAME=lucid
DISTRIB_DESCRIPTION="Ubuntu 10.04.4 LTS"
root@Danny1:/home/nolan# uname -a
Linux Danny1 2.6.32-33-generic #72-Ubuntu SMP Fri Jul 29 21:08:37 UTC 2011 i686 GNU/Linux
root@Danny1:/home/nolan# sudo rm /var/lib/apt/lists/lock
root@Danny1:/home/nolan# sudo rm /var/lib/dpkg/lock
root@Danny1:/home/nolan# sudo cp -arf /var/lib/dpkg /var/lib/dpkg.backup
root@Danny1:/home/nolan# sudo mv /var/lib/dpkg/status /var/lib/dpkg/status-bad
root@Danny1:/home/nolan# sudo cp /var/lib/dpkg/status-old /var/lib/dpkg/status || sudo cp /var/backups/apt.extended_states.0 /var/lib/dpkg/status
root@Danny1:/home/nolan# sudo mv /var/lib/dpkg/available /var/lib/dpkg/available-bad
root@Danny1:/home/nolan# sudo cp /var/lib/dpkg/available-old /var/lib/dpkg/available
root@Danny1:/home/nolan# sudo rm -rf /var/lib/dpkg/updates/*
root@Danny1:/home/nolan# sudo rm -rf /var/lib/apt/lists
root@Danny1:/home/nolan# sudo rm /var/cache/apt/*.bin
root@Danny1:/home/nolan# sudo mkdir /var/lib/apt/lists
root@Danny1:/home/nolan# sudo mkdir /var/lib/apt/lists/partial
root@Danny1:/home/nolan# LANG=C;sudo apt-get clean
root@Danny1:/home/nolan# LANG=C;sudo apt-get autoclean
Reading package lists... Done
Building dependency tree
Reading state information... Done
root@Danny1:/home/nolan# LANG=C;sudo apt-get --purge autoremove
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
3 not fully installed or removed.
After this operation, 0B of additional disk space will be used.
Setting up linux-image-2.6.32-45-generic (2.6.32-45.103) ...
Running depmod.
update-initramfs: deferring update (hook will be called later)
Failed to symbolic-link /boot/initrd.img-2.6.32-45-generic to initrd.img: File exists
dpkg: error processing linux-image-2.6.32-45-generic (--configure):
 subprocess installed post-installation script returned error exit status 17
Setting up x11-common (1:7.6+8~bpo60+1) ...
Template parse error near `<email address hidden>: Samo glavni korisnik, Samo za korisnike konzole, Svako', in stanza #1 of /var/lib/dpkg/info/x11-common.templates
dpkg: error processing x11-common (--configure):
 subprocess installed post-installation script returned error exit status 9
dpkg: dependency problems prevent configuration of xserver-common:
 xserver-common depends on x11-common; however:
  Package x11-common is not configured yet.
dpkg: error processing xserver-common (--configure):
 dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
                          Errors were encountered while processing:
 linux-image-2.6.32-45-generic
 x11-common
 xserver-common
E: Sub-process /usr/bin/dpkg returned an error code (1)
root@Danny1:/home/nolan# LANG=C;sudo apt-get update -o APT::Cache-Limit=100000000
Get:1 http://security.ubuntu.com lucid-proposed Release.gpg [198B]
Get:2 http://security.ubuntu.com lucid-proposed Release [58.3kB]
Get:3 http://archive.canonical.com lucid Release.gpg [198B]
Get:4 http://archive.canonical.com lucid-updates Release.gpg [198B]
Get:5 http://archive.canonical.com lucid-backports Release.gpg [198B]
Get:6 http://archive.canonical.com lucid-security Release.gpg [198B]
Get:7 http://archive.canonical.com lucid-proposed Release.gpg [198B]
Get:8 http://archive.canonical.com lucid Release [8215B]
Get:9 http://archive.canonical.com lucid-updates Release [8225B]
Get:10 http://archive.canonical.com lucid-backports Release [8229B]
Get:11 http://archive.canonical.com lucid-security Release [8227B]
Get:12 http://security.ubuntu.com lucid-proposed/main Packages [120kB]
Get:13 http://archive.canonical.com lucid-proposed Release [8227B]
Get:14 http://archive.canonical.com lucid/partner Packages [13.6kB]
Get:15 http://security.ubuntu.com lucid-proposed/restricted Packages [14B]
Get:16 http://security.ubuntu.com lucid-proposed/universe Packages [7738B]
Get:17 http://security.ubuntu.com lucid-proposed/multiverse Packages [14B]
Get:18 http://archive.canonical.com lucid/partner Sources [6723B]
Get:19 http://archive.canonical.com lucid-updates/partner Packages [14B]
Get:20 http://archive.canonical.com lucid-backports/partner Packages [14B]
Get:21 http://archive.ubuntu.com lucid Release.gpg [189B]
Get:22 http://archive.ubuntu.com lucid-updates Release.gpg [198B]
Get:23 http://archive.ubuntu.com lucid-backports Release.gpg [198B]
Get:24 http://archive.ubuntu.com lucid-security Release.gpg [198B]
Get:25 http://archive.canonical.com lucid-security/partner Packages [14B]
Get:26 http://archive.canonical.com lucid-proposed/partner Sources [1188B]
Get:27 http://archive.ubuntu.com lucid Release [57.2kB]
Get:28 http://archive.ubuntu.com lucid-updates Release [58.3kB]
Get:29 http://archive.ubuntu.com lucid-backports Release [57.3kB]
Get:30 http://archive.ubuntu.com lucid-security Release [57.3kB]
Get:31 http://archive.ubuntu.com lucid/main Packages [1386kB]
Get:32 http://archive.ubuntu.com lucid/restricted Packages [6208B]
Get:33 http://archive.ubuntu.com lucid/main Sources [659kB]
Get:34 http://archive.ubuntu.com lucid/restricted Sources [3775B]
Get:35 http://archive.ubuntu.com lucid/universe Packages [5448kB]
Get:36 http://archive.ubuntu.com lucid/universe Sources [3165kB]
Get:37 http://archive.ubuntu.com lucid/multiverse Packages [180kB]
Get:38 http://archive.ubuntu.com lucid/multiverse Sources [119kB]
Get:39 http://archive.ubuntu.com lucid-updates/main Packages [667kB]
Get:40 http://archive.ubuntu.com lucid-updates/restricted Packages [4630B]
Get:41 http://archive.ubuntu.com lucid-updates/main Sources [234kB]
Get:42 http://archive.ubuntu.com lucid-updates/restricted Sources [2196B]
Get:43 http://archive.ubuntu.com lucid-updates/universe Packages [289kB]
Get:44 http://archive.ubuntu.com lucid-updates/universe Sources [107kB]
Get:45 http://archive.ubuntu.com lucid-updates/multiverse Packages [11.5kB]
Get:46 http://archive.ubuntu.com lucid-updates/multiverse Sources [5811B]
Get:47 http://archive.ubuntu.com lucid-backports/main Packages [19.0kB]
Get:48 http://archive.ubuntu.com lucid-backports/restricted Packages [14B]
Get:49 http://archive.ubuntu.com lucid-backports/universe Packages [56.0kB]
Get:50 http://archive.ubuntu.com lucid-backports/multiverse Packages [1378B]
Get:51 http://archive.ubuntu.com lucid-backports/main Sources [9423B]
Get:52 http://archive.ubuntu.com lucid-backports/restricted Sources [14B]
Get:53 http://archive.ubuntu.com lucid-backports/universe Sources [24.2kB]
Get:54 http://archive.ubuntu.com lucid-backports/multiverse Sources [1633B]
Get:55 http://archive.ubuntu.com lucid-security/main Packages [473kB]
Get:56 http://archive.ubuntu.com lucid-security/restricted Packages [2867B]
Get:57 http://archive.ubuntu.com lucid-security/main Sources [134kB]
Get:58 http://archive.ubuntu.com lucid-security/restricted Sources [1267B]
Get:59 http://archive.ubuntu.com lucid-security/universe Packages [142kB]
Get:60 http://archive.ubuntu.com lucid-security/universe Sources [43.8kB]
Get:61 http://archive.ubuntu.com lucid-security/multiverse Packages [5372B]
Get:62 http://archive.ubuntu.com lucid-security/multiverse Sources [2347B]
Fetched 13.7MB in 3min 19s (68.5kB/s)
Reading package lists... Done
W: Duplicate sources.list entry http://archive.ubuntu.com/ubuntu/ lucid/restricted Packages (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_lucid_restricted_binary-i386_Packages)
W: Duplicate sources.list entry http://archive.ubuntu.com/ubuntu/ lucid/universe Packages (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_lucid_universe_binary-i386_Packages)
W: Duplicate sources.list entry http://archive.ubuntu.com/ubuntu/ lucid-backports/restricted Packages (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_lucid-backports_restricted_binary-i386_Packages)
W: Duplicate sources.list entry http://archive.ubuntu.com/ubuntu/ lucid-backports/multiverse Packages (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_lucid-backports_multiverse_binary-i386_Packages)
W: Duplicate sources.list entry http://archive.ubuntu.com/ubuntu/ lucid-security/restricted Packages (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_lucid-security_restricted_binary-i386_Packages)
W: Duplicate sources.list entry http://archive.ubuntu.com/ubuntu/ lucid-security/multiverse Packages (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_lucid-security_multiverse_binary-i386_Packages)
W: You may want to run apt-get update to correct these problems
root@Danny1:/home/nolan# sudo dpkg --configure -a
Setting up linux-image-2.6.32-45-generic (2.6.32-45.103) ...
Running depmod.
update-initramfs: deferring update (hook will be called later)
Failed to symbolic-link /boot/initrd.img-2.6.32-45-generic to initrd.img: File exists
dpkg: error processing linux-image-2.6.32-45-generic (--configure):
 subprocess installed post-installation script returned error exit status 17
Setting up x11-common (1:7.6+8~bpo60+1) ...
Template parse error near `<email address hidden>: Samo glavni korisnik, Samo za korisnike konzole, Svako', in stanza #1 of /var/lib/dpkg/info/x11-common.templates
dpkg: error processing x11-common (--configure):
 subprocess installed post-installation script returned error exit status 9
dpkg: dependency problems prevent configuration of xserver-common:
 xserver-common depends on x11-common; however:
  Package x11-common is not configured yet.
dpkg: error processing xserver-common (--configure):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 linux-image-2.6.32-45-generic
 x11-common
 xserver-common
root@Danny1:/home/nolan# sudo dpkg --clear-avail
root@Danny1:/home/nolan# LANG=C;sudo apt-get -f install
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
3 not fully installed or removed.
After this operation, 0B of additional disk space will be used.
Setting up linux-image-2.6.32-45-generic (2.6.32-45.103) ...
Running depmod.
update-initramfs: deferring update (hook will be called later)
Failed to symbolic-link /boot/initrd.img-2.6.32-45-generic to initrd.img: File exists
dpkg: error processing linux-image-2.6.32-45-generic (--configure):
 subprocess installed post-installation script returned error exit status 17
Setting up x11-common (1:7.6+8~bpo60+1) ...
Template parse error near `<email address hidden>: Samo glavni korisnik, Samo za korisnike konzole, Svako', in stanza #1 of /var/lib/dpkg/info/x11-common.templates
dpkg: error processing x11-common (--configure):
 subprocess installed post-installation script returned error exit status 9
dpkg: dependency problems prevent configuration of xserver-common:
 xserver-common depends on x11-common; however:
  Package x11-common is not configured yet.
dpkg: error processing xserver-common (--configure):
 dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
                          Errors were encountered while processing:
 linux-image-2.6.32-45-generic
 x11-common
 xserver-common
E: Sub-process /usr/bin/dpkg returned an error code (1)
root@Danny1:/home/nolan# LANG=C;sudo apt-get --fix-missing install
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
3 not fully installed or removed.
After this operation, 0B of additional disk space will be used.
Setting up linux-image-2.6.32-45-generic (2.6.32-45.103) ...
Running depmod.
update-initramfs: deferring update (hook will be called later)
Failed to symbolic-link /boot/initrd.img-2.6.32-45-generic to initrd.img: File exists
dpkg: error processing linux-image-2.6.32-45-generic (--configure):
 subprocess installed post-installation script returned error exit status 17
Setting up x11-common (1:7.6+8~bpo60+1) ...
Template parse error near `<email address hidden>: Samo glavni korisnik, Samo za korisnike konzole, Svako', in stanza #1 of /var/lib/dpkg/info/x11-common.templates
dpkg: error processing x11-common (--configure):
 subprocess installed post-installation script returned error exit status 9
dpkg: dependency problems prevent configuration of xserver-common:
 xserver-common depends on x11-common; however:
  Package x11-common is not configured yet.
dpkg: error processing xserver-common (--configure):
 dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
                          Errors were encountered while processing:
 linux-image-2.6.32-45-generic
 x11-common
 xserver-common
E: Sub-process /usr/bin/dpkg returned an error code (1)
root@Danny1:/home/nolan# LANG=C;sudo apt-get update -o APT::Cache-Limit=100000000 && sudo apt-get dist-upgrade
Hit http://archive.canonical.com lucid Release.gpg
Hit http://archive.canonical.com lucid-updates Release.gpg
Hit http://archive.canonical.com lucid-backports Release.gpg
Hit http://archive.canonical.com lucid-security Release.gpg
Hit http://archive.canonical.com lucid-proposed Release.gpg
Hit http://archive.canonical.com lucid Release
Hit http://archive.canonical.com lucid-updates Release
Hit http://archive.canonical.com lucid-backports Release
Hit http://archive.canonical.com lucid-security Release
Hit http://archive.canonical.com lucid-proposed Release
Hit http://security.ubuntu.com lucid-proposed Release.gpg
Hit http://archive.canonical.com lucid/partner Packages
Hit http://archive.ubuntu.com lucid Release.gpg
Hit http://archive.ubuntu.com lucid-updates Release.gpg
Hit http://archive.ubuntu.com lucid-backports Release.gpg
Hit http://archive.ubuntu.com lucid-security Release.gpg
Hit http://archive.canonical.com lucid/partner Sources
Hit http://archive.canonical.com lucid-updates/partner Packages
Hit http://archive.canonical.com lucid-backports/partner Packages
Hit http://archive.canonical.com lucid-security/partner Packages
Hit http://archive.canonical.com lucid-proposed/partner Sources
Hit http://security.ubuntu.com lucid-proposed Release
Hit http://archive.ubuntu.com lucid Release
Hit http://archive.ubuntu.com lucid-updates Release
Hit http://archive.ubuntu.com lucid-backports Release
Hit http://security.ubuntu.com lucid-proposed/main Packages
Hit http://archive.ubuntu.com lucid-security Release
Hit http://security.ubuntu.com lucid-proposed/restricted Packages
Hit http://security.ubuntu.com lucid-proposed/universe Packages
Hit http://security.ubuntu.com lucid-proposed/multiverse Packages
Hit http://archive.ubuntu.com lucid/main Packages
Hit http://archive.ubuntu.com lucid/restricted Packages
Hit http://archive.ubuntu.com lucid/main Sources
Hit http://archive.ubuntu.com lucid/restricted Sources
Hit http://archive.ubuntu.com lucid/universe Packages
Hit http://archive.ubuntu.com lucid/universe Sources
Hit http://archive.ubuntu.com lucid/multiverse Packages
Hit http://archive.ubuntu.com lucid/multiverse Sources
Hit http://archive.ubuntu.com lucid-updates/main Packages
Hit http://archive.ubuntu.com lucid-updates/restricted Packages
Hit http://archive.ubuntu.com lucid-updates/main Sources
Hit http://archive.ubuntu.com lucid-updates/restricted Sources
Hit http://archive.ubuntu.com lucid-updates/universe Packages
Hit http://archive.ubuntu.com lucid-updates/universe Sources
Hit http://archive.ubuntu.com lucid-updates/multiverse Packages
Hit http://archive.ubuntu.com lucid-updates/multiverse Sources
Hit http://archive.ubuntu.com lucid-backports/main Packages
Hit http://archive.ubuntu.com lucid-backports/restricted Packages
Hit http://archive.ubuntu.com lucid-backports/universe Packages
Hit http://archive.ubuntu.com lucid-backports/multiverse Packages
Hit http://archive.ubuntu.com lucid-backports/main Sources
Hit http://archive.ubuntu.com lucid-backports/restricted Sources
Hit http://archive.ubuntu.com lucid-backports/universe Sources
Hit http://archive.ubuntu.com lucid-backports/multiverse Sources
Hit http://archive.ubuntu.com lucid-security/main Packages
Hit http://archive.ubuntu.com lucid-security/restricted Packages
Hit http://archive.ubuntu.com lucid-security/main Sources
Hit http://archive.ubuntu.com lucid-security/restricted Sources
Hit http://archive.ubuntu.com lucid-security/universe Packages
Hit http://archive.ubuntu.com lucid-security/universe Sources
Hit http://archive.ubuntu.com lucid-security/multiverse Packages
Hit http://archive.ubuntu.com lucid-security/multiverse Sources
Reading package lists... Done
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
3 not fully installed or removed.
After this operation, 0B of additional disk space will be used.
Do you want to continue [Y/n]? y
Setting up linux-image-2.6.32-45-generic (2.6.32-45.103) ...
Running depmod.
update-initramfs: deferring update (hook will be called later)
Failed to symbolic-link /boot/initrd.img-2.6.32-45-generic to initrd.img: File exists
dpkg: error processing linux-image-2.6.32-45-generic (--configure):
 subprocess installed post-installation script returned error exit status 17
Setting up x11-common (1:7.6+8~bpo60+1) ...
Template parse error near `<email address hidden>: Samo glavni korisnik, Samo za korisnike konzole, Svako', in stanza #1 of /var/lib/dpkg/info/x11-common.templates
dpkg: error processing x11-common (--configure):
 subprocess installed post-installation script returned error exit status 9
dpkg: dependency problems prevent configuration of xserver-common:
 xserver-common depends on x11-common; however:
  Package x11-common is not configured yet.
dpkg: error processing xserver-common (--configure):
 dependency problems - leaving unconfigured
No apport report written because the error message indicates its a followup error from a previous failure.
                          Errors were encountered while processing:
 linux-image-2.6.32-45-generic
 x11-common
 xserver-common
E: Sub-process /usr/bin/dpkg returned an error code (1)
root@Danny1:/home/nolan# find /etc/apt -name '*.list' -exec bash -c 'echo -e "\n$1\n"; cat -n "$1"' _ '{}' \;

/etc/apt/sources.list.d/dropbox.list

     1 # deb http://linux.dropbox.com/ubuntu lucid main

/etc/apt/sources.list

     1
     2 # deb cdrom:[Ubuntu 10.04.3 LTS _Lucid Lynx_ - Release i386 (20110720.1)]/ lucid main restricted
     3 # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
     4 # newer versions of the distribution.
     5 deb http://archive.ubuntu.com/ubuntu lucid main restricted
     6 deb-src http://archive.ubuntu.com/ubuntu lucid main restricted
     7 ##Major bug fix updates produced after the final release of the
     8 ## distribution.
     9 deb http://archive.ubuntu.com/ubuntu lucid-updates main restricted
    10 deb-src http://archive.ubuntu.com/ubuntu lucid-updates main restricted
    11
    12 ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
    13 ## team. Also, please note that software in universe WILL NOT receive any
    14 ## review or updates from the Ubuntu security team.
    15 deb http://archive.ubuntu.com/ubuntu lucid universe
    16 deb-src http://archive.ubuntu.com/ubuntu lucid universe
    17 deb http://archive.ubuntu.com/ubuntu lucid-updates universe
    18 deb-src http://archive.ubuntu.com/ubuntu lucid-updates universe
    19
    20 ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
    21 ## team, and may not be under a free licence. Please satisfy yourself as to
    22 ## your rights to use the software. Also, please note that software in
    23 ## multiverse WILL NOT receive any review or updates from the Ubuntu
    24 ## security team.
    25 deb http://archive.ubuntu.com/ubuntu lucid multiverse
    26 deb-src http://archive.ubuntu.com/ubuntu lucid multiverse
    27 deb http://archive.ubuntu.com/ubuntu lucid-updates multiverse
    28 deb-src http://archive.ubuntu.com/ubuntu lucid-updates multiverse
    29
    30 ## Uncomment the following two lines to add software from the 'backports'
    31 ## repository.
    32 ## N.B. software from this repository may not have been tested as
    33 ## extensively as that contained in the main release, although it includes
    34 ## newer versions of some applications which may provide useful features.
    35 ## Also, please note that software in backports WILL NOT receive any review
    36 ## or updates from the Ubuntu security team.
    37 deb http://archive.ubuntu.com/ubuntu lucid-backports main restricted universe multiverse
    38 deb-src http://archive.ubuntu.com/ubuntu lucid-backports main restricted universe multiverse
    39 ## Uncomment the following two lines to add software from Canonical's
    40 ## 'partner' repository.
    41 ## This software is not part of Ubuntu, but is offered by Canonical and the
    42 ## respective vendors as a service to Ubuntu users.
    43 deb http://archive.canonical.com/ubuntu lucid partner
    44 deb-src http://archive.canonical.com/ubuntu lucid partner
    45
    46 deb http://archive.ubuntu.com/ubuntu lucid-security main restricted
    47 deb-src http://archive.ubuntu.com/ubuntu lucid-security main restricted
    48 deb http://archive.ubuntu.com/ubuntu lucid-security universe
    49 deb-src http://archive.ubuntu.com/ubuntu lucid-security universe
    50 deb http://archive.ubuntu.com/ubuntu lucid-security multiverse
    51 deb-src http://archive.ubuntu.com/ubuntu lucid-security multiverse
    52 # deb http://backports.debian.org/debian-backports squeeze-backports main
    53 deb http://archive.ubuntu.com/ubuntu lucid restricted universe
    54 deb http://archive.ubuntu.com/ubuntu lucid-backports restricted multiverse
    55 deb http://archive.ubuntu.com/ubuntu lucid-security restricted multiverse
    56 deb http://security.ubuntu.com/ubuntu lucid-proposed main restricted universe multiverse
    57 # deb-src http://security.ubuntu.com/ubuntu lucid-proposed main restricted universe multiverse
    58 deb http://archive.canonical.com/ubuntu lucid-updates partner
    59 deb http://archive.canonical.com/ubuntu lucid-backports partner
    60 deb http://archive.canonical.com/ubuntu lucid-security partner
    61 deb-src http://archive.canonical.com/ubuntu lucid-proposed partner
root@Danny1:/home/nolan#

I suspect that you installed packages from Debian Squeeze which broke your package manager....

Mixing repositories from different versions of Ubuntu and/or mixing packages between Debian and Ubuntu can AND will break your package manager. So it should NOT be done.

First remove the following configuration lines in your /etc/apt/sources.list file using the gedit editor:

  37 deb http://archive.ubuntu.com/ubuntu lucid-backports main restricted universe multiverse
    38 deb-src http://archive.ubuntu.com/ubuntu lucid-backports main restricted universe multiverse
    52 # deb http://backports.debian.org/debian-backports squeeze-backports main

You can edit the /etc/apt/sources.list file using this command:

gksudo gedit /etc/apt/sources.list

Then downgrade the x11-common package using this procedure:

http://askubuntu.com/questions/202477/apt-get-upgrade-fails-for-x11-due-to-some-strange-templates-error

Hope it solves the issue.

Support for Lucid is due in a few weeks time (April) so you may want to consider upgrading.

The easiest way will be to backup all your data and do a clean install.

I suggest you try Ubuntu 12.04 Precise download here
http://www.ubuntu.com/download/desktop

or Xubuntu 12.04 download here
http://xubuntu.org/getxubuntu/

Both of these are Long Term Stable releases so you wont wont need to upgrade any time soon. If you want the latest features you can install 12.10 but will need to upgrade sooner.

You can try both of these from a CD/DVD or live USB so you can decide which you prefer before installing. The same software is available for both, in the software centre, though they do have different applications installed by default. Ubuntu is more resource hungry than Xubuntu so may be a better choice if you have an older PC.

Give them a try, install the one you want, and if you have any problems ask here again.

If for some reason you are not ready to upgrade let us know and we will try to figure out what the problem is.

Thanks Mark Rijckenberg, that solved my question.