I had this a while back and it seemed to start working again just as suddenly as it had stopped.  In the meantime I had fiddled with a few of the menus and the media player menu was showing that it was playing the last track I'd been listening to on the iPod.  This cleared (I don't think I did anything to clear it) and then everything worked next time I went in.  It's been fine for 3-4 weeks now.