Of course, why should it be easy?!
So, here's some generic computer addresses where iTunes stores backups:
Generic References:
* Mac: ~/Library/Application Support/MobileSync/Backup/
* Windows XP: \Documents and Settings\(username)\Application Data\Apple Computer\MobileSync\Backup\
* Windows Vista and Windows 7: \Users\(username)\AppData\Roaming\Apple Computer\MobileSync\Backup\
Try navigating there and seeing if there are any backups there. If there are, delete any that are for your iPad and then try again (maybe even reboot your computer ... or at least iTunes, just in case). Sometimes, iTunes gets stuck...
Let us know how that goes.
Marilyn