Heffer,
as I understand it Error 22 is a grub error, to remidee this situation you can insert your Windows XP CD and run the recovery console once in the recovery console Type 'fixmbr' or 'fixboot'
If this doesn't work obtain a Knoppix Live CD and back your data up and reinstall your Linux system
I am wondering if you are using windows and Linux on the Same HDD or seperate HDDs if not than I suggest you do it makes it a lot less painful when it comes to situations like these
hope this Helps,
Jake