If PrimoDVD reports a successful copy from a known working source, then the DVD-R is ok unless it's the crappiest media.
So assuming the chip you are using is OK (like it worked before) then suspect your laser. First step is to clean it with a CD Lens Cleaner (a flail disk).
If no good, do it again.
If no good, recalibrate the DVD laser setting (
www.infofree.org - you do this at your own risk).
If no good, replace the laser.
If your chip is a NEO2.2 ensure that Pin 2 is strapped to a capcitor to prevent its 5 v frying the 3.3 v laser circuit.