No audio from purchased iTunes TV shows

I have been using Apple TV for awhile now and have watched my purchased TV shows before. However, I recently upgraded to Lion on the host computer and now I have no audio on my iTunes television programs. Other functions work fine: I have iTunes music, I have Netflix etc, all that audio plays fine. With my iTunes television programs, however, there is no sound. What is going on? (Please don't give me the noob responses like "reboot, unplug, check for updates, check settings" I've DONE ALL THAT!

Thanks,

Buck