iPod My Purchased Movies Won't Transfer..

I purchase all my media from the iTunes store. I recently purchased a Time Capsule, so I have been moving all my media over to that. However, lately, I have been getting messages when moving some movie or tv show files over that, "This file cannot be played on this iPhone."

They used to transfer, but now I'm stuck with files that only play on my computer / Apple TV. That's no good. Has this happened to anyone else? Does anyone have any solutions?