Plextor 760 trouble using dvdshrink

Hello there,
I searched but could not get the answer…

Here is the problem.
We got the 760 for my father. He uses XP SP1, dvdshrink. HD configured as RAID 1.

He is able to burn copied DVDs, but when he tried to back up DVD using DVDshrink + Nero, the DVD has been burned, but there was nothing on it.

He was using a pioneer for the last couple years with no trouble.

What are the first steps to trouble shoot the issue?
What king of information would you need to help me?

PLease bear with me as I have to do everything remotely ( father being in France, me living in Ireland…)