Can't watch downloaded movies in iTunes on Mac

I downloaded a few movies on my Macbook Pro in iTunes prior to leaving for a trip, because I knew I wouldn't have internet access. I opened the movies and started playing them at home just to make sure the downloads were fully complete, and because I've had issues with this in the past and had been told that I may need to do this while I still had an internet connection.

So, I arrive at my destination and sure enough, I can't get any of the four movies I downloaded to play. And I do, in fact, have an internet connection here (which is how I'm writing this message), but it's just very slow.

When I open the movie, I see the "home" screen with all of the options (play, extras, etc.), but when I click play, the screen remains black. What's strange is that if I move the cursor, the scrubber comes up and I can move it to any point in the movie and see the picture change. That makes sense since the movie is downloaded on my computer; but what doesn't make sense is why it won't play.

Any ideas?