You might want to download and apply HS0E or HS0K firmware to your drive, or even HS0P, as they were all good with -R media. To be honest, this problem shouldn't be happening with Verbatim DLP discs, as they are very,very good. Can you post a KProbe Scan of these discs for us? (Check out the KProbe Thread, a sticky in the Media Forum).
ALso, those G04s are good, but users have been reporting loads of problems with some G04s, so you might want to be careful and pick up RiData 4X -R discs which ought to be the best among the lot.
EDIT : On rereading your post, it sounds like DVDDEcrypter problems. I'd suggest using SmartRipper + DVDSHrink. They've worked perfectly for me so far.