Did you make the menu yourself? I usually don't bother putting menus on my dvd movies that I burn with nero... dunno why. Anywho. Is the video in a weird format? Are you able to watch it on your computer (not that you should watch it on your computer, just scroll through it quickly and make sure that it's all functional video)?
Lastly, if there's any other details in the error message other than unknown error (unlikely), please post that. And it's possible that you would be better off getting help for this kind of problem in a place like this.
P.S. you may want to try reinstalling/repairing nero in case something got corrupt?
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"Strong am I with the Force, but not that strong.
Twilight is upon me, and soon, night must fall.
That is the way of things. The way of the Force."
--Yoda