I think I have found a bug but would like to check and see if this is happening to others.
Try opening the attached (simply jit.window #1) inside a bpatcher.
Max crashes every time for me. I notice that jit.window first shows up with a randomly generated uxxxxxxxx name, then the crash happens so it could be something to do with a conflict between the randomly generated file name and the #1.
Max MSP JItter 5.02
OS X 10.4.11
MacTel 2.33, 2gb