I've been experimenting with this a little more. I can pause, resume and fast backward just fine betweem the start/first set of commercials and the second set of commercials. After the second set of commercials, which start with some scrambled video, when I pause or fast backwards it goes back to the scrambled video/start of the second set of commercials. So it's starting to really look like it's this scrambled video that's causing problems. Maybe it's not edited in properly?