There is an updated codec included in the "upside-down movie patch" which you should install if you haven't yet (see the FAQ). In fact, that's all the patch is.
If that doesn't fix it, it's possible that your disc is bad or something. You can try moving the movies to the hard drive (also in the FAQ), and then replacing that movie with another (good) one to try to get past that point.
Otherwise, you can have someone play past that point for you like Synergy Blades suggested.