Some older applications look at the location referenced by the pointer FCBSPtr, which in OS 7 and OS 8 contained a list of open files. Apple considers this method deprecated, and applications that attempt it will terminate with a message such as: "This application is incompatible with OS9. Please contact your software vendor to obtain a newer version of this application."

The full description of this problem (designated Error 119 by Apple), can be found here. In short, Apple has made some rather major changes to the structure of the FCB in OS9, and is 'encouraging' people to use OS9 compliant applications by halting older apps when they make an outdated call.

There is a solution, however, since Apple's termination of these applications is more precautionary than anything. Akua Software has made a small extension called Nine11 available that implements a trap to catch references to the FCBSPtr pointer, and allows you to continue using older applications. The author points out that there is a chance that memory instability could result (a dialog isn't expected by the application), or that the application could try to open multiple copies of the same file.

I've been using this patch for a couple of days now, and have found that it allows ZipIt to run again (but attempting to drag and drop into an archive causes a crash). Even better, I can now use my Color Quickcam 2 again, since the extension seems to patch around the problems with Connectix's software without any issues.