You’re probably missing the video codec for the file. To find out which codec you need, feed the file into one of the diagnostic tools on this page.
Pay particular attention to the fourcc and file type.
Hi this happend to me, I then downloaded/purchased haha, Nero 7, This fixed the problem for me as if came with the codecs and plays pretty much all video file sources in nero vision. All so have you tried running it through power dvd?