Itunes keeps freezing up when trying to play a rented movie.

I recently rented a movie from itunes using the $2.99 SD copy. I downloaded it and then prepared to watch but instead of playing the movie freaked out and froze my itunes. The only way it would do anything was when I exitted out. I've tried restarting my computer twice, have opened and closed itunes mutliple times. I believe I have the most recent version of itunes (11.02). I have 24 hours to watch my movie and it is not working! Help please! Is there any way to fix this. I've tried making sure itunes is the only thing open, but even then it doesn't work.