I also had this prioblem.
If you already ahev Windowz on that machine than i think that may haev something to do with it.. (I had it XP on the same machine) I re-installed my linux box.. and there was an option to write LILO to the Mastre BOOT record (MBR) or to a seperate partition...

I got L 99 99 99 99 99 99... when i wrote it to a bootable partition.... but i got my regualr boot when it was written in the MBR.

Give that a shot and se if it'll work.