Error 0x20 in LILO

I recently installed Linux on my 486. I did it by hand, as the installation program requiers too much memory. But I forgot to install LILO.

Now I try to use a boot floppy from my other computer. But when I try to boot this happens:

LILO boot:Loading linux
Error 0x20
boot:

I checked the LILO User’s guide, and it says: 0x20 “Controller error”. This shouldn’t happen.

What do I do now?