Sounds like Nero is having a problem converting your sound files to wave files.
The first thing I would try would be to use WMP 11 to burn an audio cd and see what happens. If it works then it is likely that Nero may have a corrupt audio codec. (also try different audio files to begin with to make sure it isn't a corrupt original...as I've never had a problem with Nero)
You can also check to see if there is updated firmware for your drive
What errors are you getting from Nero?