Liteon 5002 jittery playback



hi guys…got a liteon 5002 a couple of weeks ago, downloaded the firmware updates…all working great. well impressed. using it to dump down from sky+. a mate of mine gave me a dvd he burned on his pc. 5002 recognises it. on play i do not get the menu screen, the tv show auto plays and the playback is jerky. apart from the jittering the picture quality is great and the dvd plays on on pc’s and a couple of stand alone dvd’s.
Any ideas guys?
many thanks in advance

chris N