Well again thanks for all the help as it turned out, none of my authored copies I tried played all the way through on the symphonic player, including a version I broke in split in order to get high quality, so I had a part one and part two; however when we put the same disc in a newer player it played well. The same disc played fine in my laptop, and my home computer and DVD player.
I like Hardin's idea about "bit setting to be changed to DVD-ROM for 'plus' media" I guess it's just the player. I tell people to try it out on someone else's player to make sure it's not the disc.
One other problem I notice when I give a disc to someone to try, they put it in the same player that the kids use to play their dirty, sticky, scratched disc in so that the laser heads are out of alignment.