boot from a live cd or disk 2 and give the option root=/dev/hd?? where ?? refers to whatever your root (that's /) partition is, at the boot prompt.
that should dump you into a shell and you can try to rerun lilo again and see if it does update.
or as a last resort since you just installed, is to just reinstall again and make sure you configure lilo and install it to the MBR (which isnt as unsafe as it says!) its actually the only way i have ever gotten it to work.. LOL
hope that helps you out.. let us know if it doesnt work and ill see if i can help you out more.