The Problem is, that the new 3.1 installation has overwritten then 68040.library with the "full" one. You have to reinstall that dummy 68040.library that redirects all calls to the 68060.library.
Boot from a disk that has no setpatch in it`s Startupsequence (that triggers the guru) or boot without startupsequence at all and exchange the 68040.library and you are set.
