Also and BTW, I know nothing about dvdfab since I have never used it. But I doubt your backup software choice is the problem. So my above advice is generic to whatever program is used.
What brand, type and rated-speed is your media?
And what speed are you burning it at?
Burning to slow can be as bad as burning too fast. In other words if your drive’s firmware has write strategies that will burn 16X rated Verbatim +R blanks at 16x, 12x and 8x but you are burning at 4x (assuming you will get a more reliable burn), then your burner may default to a “generic” or “non-optimized” 4x writing strategy that is not specific to your Verbatims … which is not a good thing. I have also read that too slow a burn can cause burn/playability issues by causing too much “laser-heat” to be applied to the thinner foil of the recording layer meant to be thin in order to accept faster speeds. …but that is second hand information and I can’t attest to it’s accuracy.
The BenQ DW1640 is a hall of fame burner, being one of the best drives ever marketed.