Does Nero burn these discs ok ? If you have been around these forums and its predecessor a while you may have seen a lot of problems with the dye on the discs your using ! CMC MAG make just about the crappiest most unreliable dye out there.....
From the message above it appears that your drive doesn't like the discs - I use Grade A Ritek G05 dye as well as Taiyo Yudens and don't have the problem your getting.
My advice is to change the dye/discs and try again.....