Bought a Spongebob TV episode for my son on the My iPod Video. It would play as a simple audio program (no video would play).
Didn't want to pay for Apple Support call. And got a standard template response (with about 7 tips) from Support when I requested a refund from iTunes for that episode.
None of those tips worked. Googled a lot, and many web sites had other tips. None worked.
Finally, go to topmost menu, and under SETTINGS, choose "Reset all Settings". Voila.