I was playing with remote control codes and got my DMP-BD65 into a state where it will not eject the disk, LOCK appears on the display when open/close is selected. Unplugging it and setting setting back to factory does not clear the problem. I think the software has the player thinks it is either recording or erasing the disc (even though this player does not suport that feature) and has it locked until the operation is completed or cleared.
With the unit turned on push open/eject and the play button on the unit at the same time until unlock appears in the display. Should be about 5 seconds. Play button is behind the little door on the bottom of the front (oppisite of the display).