Thanks to Akuna and Gapan for helpful info. Lilosetup generated different addresses for partition sda3. When I used that lilo.conf, the problem disappeared.

One comment. Apparently lilosetup is only available in "full" installs. Since it may be needed in other install flavors, perhaps it should ...

I have attempted to install Salix in four different flavors: Fluxbox and Ratpoison, each in full and basic. The same problem occurs with all four install types.

I am installing Salix on a multi-boot machine, next to Slackware (sda1) and Arch (sda2). Slackware boots from the disc MBR; Arch boots ...