SANE should trap these and route them to emulator routines for most programs. For the remainder, see below. I'd question your SSW installation if you're getting errors often for "standard" stuff. Mathematica and raytrace programs yes (A/UX definitely- but that won't run on a PB anyway) Netscape, StuffIt, etc. shoud not need one. 7.5.5 or (even better) 7.6.1 would be a better choice for SSW. In my dim recollection, 7.5.3 was a buggy release. 7.1 was pretty good if you wanted to go older. get SoftwareFPU and try it. Some LC040s have a bug that interferes with its operation, some do not. A quick trick to see if there should be a problem is to try to run the software on a PPC Mac - the 68k emulation is LC040 (no FPU). I'm not sure how the PB540 does the CPU - desktop Macs had them socketed, so you could drop in a full 040