Recent iTunes Videos Won't Play

Here is an odd one...over the last three months, I've purchased all of the episodes to Eli Stone and loaded them on my iPod (that's a terrific show, by the way). All of the episodes view fine on my MacBook Pro running 10.4.11. The first 10 episodes all worked fine on my iPod, but the last two will not play, no matter what--no video, no sound, no nothing. I've deleted them and reloaded them, no change. One thing that coincided with the start of the problem is that I upgraded my iPod software to the current version, but not sure why that would cause this problem. Every other file on the iPod works fine, just these two pain-in-the-behind Eli Stone episodes. Any idea what the problem is and how to resolve it?