Postby b-frame » 13 Jun 2011 19:44
Well, you don't provide too much information. Show us some error log (Tools->Messages, Verbosity Level=2, jump to position, hit play again).
Probably, the file is somehow broken. If so, try to just rip the DVD again. Maybe there was a read error caused by a damaged DVD or copy protection. If this is a double layer disc, it may be the position where the data continues on a new layer.
Btw, did you try to play the file with another player yet?