Nero v6 queries

I have been using nero v6 for copying cds using a cd rw and have ran into some difficulty when doing so.
When I try and convert mp3 tracks to normal audio it gives me burn process failed although if I burn just mp3 i have no trouble.
The other problem I have had is burning dvd rips that I have dowmloaded onto disc. Although the rips are lesser than the capacity of the disc (if only by a mb) it says the total disc capacity used is way higher when i go to burn around (5-600 mb more). I have tryed editing the optiions with no joy. Can anyone help me? I hope so! :sad:

What version of Nero 6 are you using when you get this error? Can you be more specific than Nero v6?