Movie rental - not enough space on ipad

Hi

I rented a movie from itunes on my ipad. It took a while downloading. Then it said processing for a long while too so I opened the videos app to find my movie and I got a message saying that there was not enough memory.

Now I can see the movie icon on my videos but the movie doesn't play. I checked the support site and it says that if I rented from the ipad I can't see it from another device... what should I do?

Cat