Here is what you were asked to do. I did it on my system, and am posting the results to show you how.
Open a konsole, and use the 'su' command to get root privileges.
[root@Duelie cliff]# fdisk -l
Disk /dev/sda: 160.0 GB, 160040803840 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x16001600
Device Boot Start End Blocks Id System
/dev/sda1 * 1 1784 14329948+ 83 Linux
/dev/sda2 1785 19457 141958372+ 5 Extended
/dev/sda5 1785 2038 2040223+ 82 Linux swap / Solaris
/dev/sda6 2039 19457 139918086 83 Linux
You need the root password, you would set that up at install time. Then run the command 'fdisk -l' ( without the quotes ).
The ID field identifies the file system type. 83 is ext3. 82 is swap file system.
Once you know what partition number, and the file system, you run the command 'fsck.ext4 /dev/sdaX' This would be for ext4, the default for Ubuntu 9.10. You need to use the correct partition number, my system has sda1 and sda6. Yours will have possibly the same, or different depending on the types of harddrives, and the partitioning scheme you have.
Hope this makes it easier to follow.