couldnt install ubuntu inside windows

are you sure that in installation you selected "C:" drive? not custom or not existing drive?

ya i selected c: drivw

This is caused by:
1. minor partition table errors
2. an unsupported raid (e.g. 0 or 1+0)
3. a disk with leftover GPT data e.g. a disk previously used on a mac

You can fix the first with a partitioning tool. You should know if you have a raid for the second. And the third might be tough unless you know your disk came from a Mac previously or was used for GPT

If you proceed with the install until the error, drop to a terminal Ctrl+Alt+F2 and run:
sudo parted -l
(lower case -L) it will tell you if there are partition table errors

If you run:
sudo fdisk -l
you may be able to see the errors and it will say if there is GPT data

sudo blkid
should give some idea if there are problems identifying the disks/partitions (as in an unsupported fakeraid). All commands case sensitive.

To exit type:
sudo reboot

how to correct the partition table erroe wit partition tool

The partition tool should tell you what's wrong and be able to fix it. I'm not a partition table expert. If you can confirm what the problem is then I'll look for some references for you.