Switched mobos and need to repair WinXP pro, but PC will not boot

I just switched out my ABIT motherboard and P4 CPU for a Shuttle AN35N and AMD 2600+ CPU. I'm trying to do a repair of my Windows OS with my WinXP Pro CD (legal version) but cannot because I keep getting this: line 6352 of the INF FILE \\i386\\ TEXTSETUP.SIF is invalid, setup cannot continue

What is causing this and how can I get out of it? I know I should do a complete reinstall but I need to back-up some files first before I do that, but since I can't even get beyond the message above what is the alternative?

use a knoppix CD. It can access a NTFS partition just fine. Or use PEBuilder