I don't know much about OSX, but if I had to guess I would say someone is trying to dereference a NULL pointer.

Since you don't show any code, I can't help you much. Try to move both programs to the same folder to see if paths have anything to do with it. Run a trace or debugger alongside. Call a copy of the first program somewhere else to see if the error depends on reopening the same file or if it is the contents that does the harm.