Application Unexpectedly Quit
Applications quit without warning when they either run out of memory or encounter a conflict with an incompatible (usually out-of-date) system extension.

TYPE 1 Errors
This often means your program has ran out of memory. The application tried to access a chunk of memory that didn't exist or needed more RAM than was available. You can remedy the problem by allocating more memory to the program, adding more RAM to the system, or simply restarting your Mac so the RAM available is in contiguous chunks.

TYPE 2 Errors
Are also related to memory use. The Mac tried to store a chunk of data in an address that couldn't hold it.

TYPE 3
Errors are called an illegal instruction errors. It means the Mac tried to execute an instruction that isn't part of its standard vocabulary. The cause may be an out-of-date system extension or hard disk driver.

Errors 17-24
These errors indicate that the Mac tried to access one of the standard routines in the System file and couldn't find it. In all probability, that means you have a corrupted System file. Try installing a new System file to replace the damaged one.

Error 25
Once again, your've run out of RAM.

Errors 26, 27, 30, 31
Apple says these errors tend to appear when your System file has gotten mangled. Replace it.

Error 28.
This error is accompanied by the message Stack ran into heap, but that's just another way of saying you ran out of memory.

Type 11 Error
On a Power Macintosh, a Type 11 error can mean almost anything. It simply refers to an error that occurred in reading native PowerPC code. Usually it means a bus error, an address error, or an illegal instrution.

Error -39
A -39 error is usually accompanied by the message end of file or no additional data in the format. This error points in the general direction of a corrupted file. It means that the mac started to process a file but couldn't finish reading it. If you encounter this message at startup, it could mean that the launcher has become corrupted. All you have to do is drag the launcher control panel into the trash and reinstall it.