Overburning DVD+R media is limited to a few drives, and no drive has been reported capable of overburning DVD-R media.
Going by your signature, I don't think you have a drive capable of overburning. :disagree:
Drives that can overburn DVD+R:
Plextor PX-760, PX-716, PX-712 (perhaps PX-755 with future firmware)
BenQ DW1655, DW1650, DW1640