Are you getting a "power calibration error" reported from nero?
What's the media ID of your blanks?
Download DVDInfo or launch Nero's "CD-DVD speed" go to extra hit disc quality test ... look at disc info you'll see type and ID ... ID will tell who made the blank.
what speed are you burning at?
Try installing DVD decrypter and then use DVD shrink 3.17 ... using DVD Shrink 3.17 save the file as an ISO and then try burning with Nero.