I have a Samsung BD-P1600, not sure if it's the same as yours.
I have also noticed a few discs that would not play, usually a firmware update will fix the problem.
After some lengthy hesitation in the player, Avatar does play on mine.
I suggest taking the player back to where you bought it to see if they will replace it or help you out with sending it off for repairs.
Sometimes stores will try to help you out like that when problems happen.