Probably a bad burner. Or the disc isn't being closed properly. Try patching nero to the latest and try again. Or see if your CD-burner has a firmware update. Sometimes that solves those issues.
If all else fails, do what Kim did.
"Speak English... I am speaking Engrish..."
Steve Chang
99 Silver SVT Contour #196 (Garaged)
06 Dark Blue Pearl Fusion SE V6 (Daily)
05 Dark Shadow Grey Freestyle Limited AWD