Thought I'd share a bit of info I got as a result of trying to play some of our Region 1 DVD's in our New Silverback 29RE. Out of the first 5 DVD's we tried, three would not play and presented us with a Disc Region Issue. We know the DVD's are good, and work in all of our other players. Mike the Service Manager at American Coach got in contact with Forest River and provided me with the "HTS-1500 Tech Bulletin.pdf" that details the issue and how to work around it.
You can get a copy of it at the following Link: Region Error Technical Bulletin
It seems to work, but take note in Technique 4's note 4 in reverse also. If the Disc has less that 16 chapters, the highest number in the "C" column will be the number of chapters. In my case I had a 15 chapter Disc, so the last column read 13, 14, 15, 15.
Hope this helps someone,