Power calibration error's are coming from your burner,
not dvdFab.

Now I use Plextor burners and in the past when I got the same error,

I would remove the unit,
open it up, moisten a Q-tip with alcohol and gently dab the lazer lense.[ tiny little glass looking thing which you cannot miss.
Although I could not see anything on the lense,
it obviously had some film of either smoke, dust or whatever.
anyway,
put the unit back in, and all was back to normal.

btw:
I only did this when unit was out of warranty.
So if you do this ,
do not uninstall your burner thru windows.
Just shut down, remove it, clean, put back in, and turn back on.
Your PC will be non the wiser..