After trying myriad things to try and resolve my inability to play purchased DVD movies it is now resolved.
Previously, I had been using the "hacked" firmware available on "Dangerous Brothers" website, which are "Region Free". I decided, after reading the notification on this forum of new factory firmware updates for this drive to update to the new GSA-H10N - JL12. Doing this fixed the problem for me.
I thought others who might encounter this problem might benefit from my experience.
WHY none of the "hacked" firmware versions allowed the playing of DVD movies in this drive, especially when they are "Region Free" escapes me. But then again, I am not that knowledgeable of how all this stuff relates together.