I've got the same problem, when exiting the game (fullscreen) it crashes, but since I use VISTA now i have no problem terminating the process. As MLeo already said it is trying to do something where it shouldn't. I think the autor might left out a command at a teminate function, a simple check if a mission still exists or something like this...
So far for the traceback error...
But what all that statements before that are, I don't have a clue where your install prints that... :?