From Apple's Tech Info Library:A Type 11 error is listed as a hardware exception error. However, As with all Macintosh Type xx errors, they usually do not identify a particular software or hardware component error. Type xx errors are more general in nature. You may see more Type 11 errors on a Power Macintosh computer because of problems with the software-based 68k emulator. The emulator allows the RISC processor to run older Macintosh software. If the emulator gets corrupted while loading into RAM, then some of the failures caused by this are reported as Type 11 or Hardware Exception errors. The emulator can get corrupted by either incompatible software or faulty hardware.This error is common with OS 7.x. The Read Me for OS 7.6.1 claims that it "eliminates virtually all Type 11 Errors" (it should post a more descriptive error when there is a problem).