Are you trying to burn a DVD movie?
I use DVDFab to record the movie, choosing DVD9 (dual layer)
Using DVDFab is copy to an ISO file.
After the ISO file is recorded, I have the option of recording with DVDFab,
or if you are using windows 7, if you click on the file you will have the option of recording the ISO file without using Nero 9 or DVDFab.
Windows 7 has the option of recording the ISO file to your DVD burner.
I have had no trouble recording DVD+R DL like this
Armand Robert firstname.lastname@example.org