I also have a same trouble on last two shows. After I've changed video in bin picker, new video start to play(for a fading time, 1 second) and then Isadora hang without any response. Then "Application doesn't response" system message appears and a have to restart Isadora immediately to continue show.
In try-out time everythings worked fine! On last show i've recorded all show's operation in Isadora by External camera. In few days i will demonstrate this moment. Maybe it could help you to find source of problem.