root file system not defined using wubi

What video chip do you use?

use the partition that have linux compatible file system or make some new partition first.

i am trying to install ubuntu in E drive whereas,my windows is in C drive.

i use VIA chrome9 HC IGP family WDDM display adapter

Thanks shahzeb khan, that solved my question.

still not solved the problem.......wubi doesn't provide any option of partitioning in lnux compatible file system

If you unpartition the NTFS, you can then install Ubuntu to the free space. Obviously this will destroy any data on the partition...

sir.....i dont understand wat u mean by unpartition the NTFS?

Your 'E drive' is a partition on your drive, if you delete the partition so that there is free space, the installer will use it

This problem (no root file system is defined) is due to:
1. partition table errors that Ubuntu doesn't tolerate (but Windows isn't as fussy)
2. an unsupported fakeraid setup
3. a disk that previously had a gpt partition table that wasn't totally cleared when it was converted to a MBR partition table

Of those, 1. is the most likely.

To find out the issue, unfortunately you either need to repeat the process and when it fails, drop to a terminal Ctrl+Alt+F2 and enter the following commands (those are lower case -L's and note they are case sensitive):
sudo fdisk -l
sudo parted -l
sudo blkid

(the first command will specify a diagnostic if there is partition table
problems, and will say if there is GPT data present;
the second will just say there are errors if there are
partition table problems, the third might provide info if there is a
raid in play)

OR, boot from an Ubuntu CD/USB in live mode (select "Try it" without
installing) and run the http://bootinfoscript.sourceforge.net/
Place the result of the bootinfoscript on pastebin and post the address
here