"I have both knoppix and LNX-BBC, does anybody know how to fix lilo with one of those?"
Boot the rescue CD.
knoppix mounts all of your partitions so first umount your / partition, for example:
mount your Linux / partition, for example:
mount -t ext3 /dev/hda3 /canary
Do whatever editing is necessary to /canary/etc/lilo.conf
chroot to your / partition:
Be prepared. Create a LifeBoat CD.