I'm using a 68K Mac (non-Power Mac)and my system often crashes. I get the error message, "An error of type 1 has occured." when using ChemDraw.
Many applications, such as CS ChemDraw and CS Chem3D, were enhanced to take advantage of temporary system memory that became available with the introduction of System 7. Unfortunately, 68040 machines running in 24-bit addressing mode have problems with temporary memory resulting in system crashes or freezes when applications try to access it.
If you are using a 68040 machine, you must make sure 32-bit addressing is ON. To turn 32-bit addressing on, go to the Apple menu and choose Control Panels. From the Control Panels, choose Memory. Turn 32-bit addressing ON and restart your computer.
NOTE: Some other applications may not be 32-bit clean, and may have trouble running in this mode. An incompatability of this type of interest to chemists is found in versions of STN Express earlier than 3.1.2.