I believe your lilo.conf is still intact, with no errors, please check.

What you have to do is boot your knoppix cd with cheatcode
knoppix 2 so that you can go straight to commandline.
I believe your xp partition is hda1.
Type this:
mount /dev/hda1 /mnt/hda1

chroot /mnt/hda1

lilo

then reboot : shutdown -r now