Adding this. I just finished testing all of the "bad" disks in my cheapo Acer notebook. All played without issue.
I truly think this is the problem (providing it was a good burn to begin with, of course), and not the disks/burners/software themselves.
This would then make sense why some users reported certain software would burn the disks fine while others would not. I suspect that the problem-free users were only playing these disks in there PC's, and not stand-alone players! Make sense?
I suppose too that this could be a combination of the player, and the fact that some burning software may not write the layer break correctly. I'm testing pcgedit now and will report back.
Keep the reports coming.