Since SystemRescueCd-0.3.0, it was required to have at least an i686 CPU (Pentium-Pro processor or newer) to be able to run SystemRescueCd. This was because the glibc on gentoo required i686 to compile. So SystemRescueCd-0.2.19 was the last version that supports old processors (between i386 and i686).

The support for old x86 32bits processors has been reintroduced in SystemRescueCd-1.0.0. An user reported in the forums that there was no problem anymore with the glibc-2.7 in gentoo, so I recompiled all the packages for i486. And it worked.

So if you want to use SystemRescueCd on a computer using a processor older than i686 (or with a smaller instruction set) you will have to download SystemRescueCd-1.0.0-rc1 or newer.