The screen full of 99s seems to be strictly a slackware problem. I have installed about a dozen linux distros on hdd, only slackware has given me this problem. From what I have be reading this is an old, common, problem with slackware. I guess Volkerding just hasn't gotten around to fixing it.

I downloaded the slax livecd, I am using it right now. It seems to work well.

Previously, I tried to install slackware 8.1 on my hdd. The install seemed to go well, until I tried to boot - then I got the 99s.

So can I fix lilo with the slax live cd?

Yes. Mount your slack partition in Slax. Then open a terminal and do this:
(assuming slack is mounted to /mnt/slack)
chroot /mnt/slack
lilo