While adding a FAT32 drive as bootable to that other OS to my system, the
installer allowed me to create a label that is invalid for Lilo. The label
included a space. When lilo was then run from the installer, it complained
about a syntax error close to the label area, lilo did not write the new
boot block, and the system was unbootable. The  installer needs to

A) check that the value entered for the OS label is valid for lilo
B) check that lilo was successful.

The installer used was the one on the CD, so one or both of these problems
may have been addressed in the update to the installer (but how can you use
the new installer before you install?? :)