The files may not be compliant? What exactly are you doing, converting AVI files to DVD format in the form of BIN/CUE files? If that's the case, it sounds like the conversion program may not be creating DVD compliant files.
Edit: actually, Nero probably doesn't even 'care' if the content of the Bin/Cue files are compliant, short of the files being corrupt (and I doubt that), Nero probably will burn the files regardless of what's contained within them. I'm not very familiar with Bin/Cue files, hopefully someone that's more familiar with them will recognize the problem. The only Bin/Cue files I've had, I burned with other programs than Nero (Alcohol 120%, CloneCD, DiscJuggler?), no reason that Nero shouldn't be able to handle them though.