Sorry about the delay.
You are in the Nero Forum and I hesitate to suggest an alternative but you might want to try DVDFlick (to eliminate Nero as a source of the problem). It’s always possible there could be a problem with your Nero version that could be solved by cleanly removing and reinstalling but trying DVDFlick would be quicker.
If DVDFlick has a problem, I suspect there is a problem with your file.
If you ever need the latest Nero 8 update, get it here:
The Nero clean tool remover is here: