I stopped downloading entire seasons of a tv show due to files being corrupted. I have found that if you download 3-4 episodes at any given time you will be alright. This of course has nothing to do with your current problem but might help you in the future.
I am use you will be able to re-download anything that is corrupt, i dont see a reason why apple wont allow you to do so. A polite email to tech support will do the trick.
Please tell us if does or does not work for you.