Comment 5 for bug 445995

There were some chances in that function for a divide by 0 error. I have added code to ensure we dont ever hit those cases however elegantly handling them seems to be something of a more interesting question. The crashes should stop however, if not please re-open. Also if anyone who reported this bug can provide exact steps to replicate that would be awesome, going from stacktraces is handy but sometimes not quite enough to fully see whats going on.