we've had problems with our DVD players but it turn out it was not the player but where we had it. It's in a cabinet on top of the receiver.
We had spacers so it wouldn't overheat but that wasn't enough. After buying another DVD and it had the same problem, we decided to put a small fan - on of those cheap clip on fan thats about 8 inches in diameter to the door of the cabinet. When we play out DVD, we fire up the fan. Works like a charm.
Check the circulation, it may be overheating.
denise