help button not working

Where is 'help' located?

Since you didn't assign your question to a package please provide information which 'Help' button in which app you mean, thanks.

problem refers to the 'general' help button (in my case, located left side of status bar). If I access help thru the menu (System>help and support), that doesn't work either.

The access to other menu and submenu entries, e.g. Application, Places, System is ok?
Any similar issues with icons (symbols) on the panel?

Please open a terminal.
applications -> accessories -> terminal
and type:
yelp

Please post the output.

Which Ubuntu?
Terminal output will show:
lsb_release -d
uname -a

https://help.ubuntu.com/community/GnomeTerminal
https://help.ubuntu.com/community/UsingTheTerminal

Sam- there are seemingly no other issues.

mrlee@mrlee-desktop:~$ yelp
Could not initialize gecko!
mrlee@mrlee-desktop:~$ lsb_release -d
Description:    Ubuntu 10.04.1 LTS
mrlee@mrlee-desktop:~$ uname -a
Linux mrlee-desktop 2.6.32-24-generic #42-Ubuntu SMP Fri Aug 20 14:24:04 UTC 2010 i686 GNU/Linux
mrlee@mrlee-desktop:~$

Seems to be a xulrunner issue.
Maybe try updating the system first:
sudo apt-get update
sudo apt-get upgrade
sudo apt-get -f install

If this doesn't work, #24 in bug report suggested:
- Quote -
Solution:
In /etc/gre.d
Delete old file 1.9.1.9.system.conf
Rename new file 1.9.2.8.system.conf.dpkg-bak to 1.9.2.8.system.conf
- End of Quote -

mrlee@mrlee-desktop:~$ In /etc/gre.d
In: command not found
mrlee@mrlee-desktop:~$

Erratum: it's answer #14 not 24.
Did you actually read the bug report yourself at all?
The sentence of Morton means, in_the_directory /etc/gre.d ...
So please take a look in the directory to verify which file it contents:
cd /etc/gre.d
ls

https://help.ubuntu.com/10.04/basic-commands/C/

yes- read the bug report (#14), but how do i rename the file? do you need further info?

thank you Sam