I have almost the same problem.
I had burn one "memorex DVD+RW 4x" disk, the movie burn from IfoEdit "Split-to-2DVDR's".
I am using nero 184.108.40.206 to burn the disk, before process burning the disk I got a worng message. The message can be "can not play by dvd player.....continue or not?", then I force to burn the disk..........
After burned, dvd-rom, dvd player not even my PX-708A can not recognise the disk, so I can not erase the DVD+RW disk!!
If any one know how to solve the problem, please let us know!!