Use any of the following media except Memorex and TDK. Not that they won't work. They simply do not have the track record for reliable playback that these 3 brands do .....
Verbatim, Taiyo Yuden, or Maxell DVD-R.
I suggest burning a disc image to the desktop. test the image with apple's dvd player. Assuming it plays as expected, lower the burn speed to 4x or lower and use any of the 3 choices I recommended above while troubleshooting on this forum.
Message was edited by: SDMacuser