First thing to do when working with BD for the first time is to use a BD-RW or RE,and make sure that you format it before the first use.
then you should take note as to whether or not the movie is BD+ encrypted, Fab is still having some issues with + part.
then are you sure that the region code is set correctly as are your other setting.
then is your hardware current on updates.
I personally have not had any issues with backing up BD movies, with the exception of some BD+ so I wait until fengtao gets the bugs worked out till then no one touches those disc's till they can be backed up.
hope this helped.
PS in the future you should start your own thread.