Have you set your HD-DVD players to 24fps output? I just did a search on the model numbers of the players mentioned and there seems to be a problem with those players playing certain DVD's if it is set to 24fps output. try setting the output to 1080/60 and see if that works. i also saw some threads that mentioned the A30 & A20 have some audio issues that can cause some DVD's and HD-DVDs to freeze during playback. This does sound like the problem you are having