my new blueray player philips bdp3300/12 is freezes after approx. 30 minutes of playing DVDs. turning it off/on doesn't seem to help as it starts to say "unknown disc". if i unplug the player from the power and wait 5 minutes or so, it starts playing, only to feeze-up again in 30 minutes.

could someone tell me what the problem is? how to solve it?