This is a bug that a lot of people get,but Nero don't seem to acknowledge it.
One way is to write it to a hard disc folder first.
On the last screen called "Burn Options", right before you press the BURN button in NeroVision, you would select "Write to Hard Disk Folder" from the menu in the upper right-hand side of the screen instead of burning direct to disc.
Then you can go to this folder later and burn it from there.
I also remember Nero burning rom always gave me problems,so i used to burn discs using Nero recode instead.