Do the DVDs play fine in other decks? (maybe a friends if you don't have a stand-a-lone).

The first thing I would suggest is cleaning the DVD. I had the same problem with some DVD's fresh out of the boxes. I now keep a CD/DVD cleaning cloth next to my player, and clean (wipe off) every DVD I buy. Haven't had a problem sense.

Don't know if my player is extra sensative to dust or what, but my solution is cheap and it worked for me.