Apple indicates that this Sad Mac code is actually “nothing”. The error falls into the software problem category.
You should never see this code on your Mac (if you believe Apple’s information).
If you actually got this code, then Apple’s documentation is wrong (It wouldn’t be the first time).
This error was listed in a table from the book: “Encyclopedia Macintosh” by Craig Danuloff and Deke McClelland. They list the problem as an Unimplememted Trap error. This is the same as a “Type 12“ error.
What to do
You should review the explanation of error “12" (using the “Mac OS Errors” option of the Tools menu).
If you suspect that the System file is corrupted, try re-installing it. If that fails to solve the problem, you are probably having a hardware failure. The System file can appear to be corrupted because of bad RAM or a bad disk. These possibilities can only be evaluated with certainty by an Apple Repair shop. Consider having your system examined if you don't feel capable of doing it yourself.