QUOTE(excaliburlives @ Jan 5 2012, 06:58 PM)

XDG3 will not play on LT2.0 you need the new LT+3.0
they will play on lt 2.0 if you have an older model disk drive. but they must be burnt from an ihas with burner max. truncated games are a severe ban risk as it cuts off data that would normally be located on a retail pressed disk. the main difference between retails and backups, in this case, is that pressed copies are pressed all the way to the edge of the disk, giving enough space. now. backups are standard burnt disks, and most drives are not designed to burn to the very edge for the fact that on commercially bought disks, there is a lack of dye (the material that the data is physically burnt on to) around the edge, so they shorten the actual capacity of the disk.
this would be why some backups do not work, especially if you truncate (cut off) necessary data.
any drive that is a part of the newer set of revision drives, must have lt 3.0 as they support ap2.5 and such technologies.
EDIT: an explanation straight from the horses mouth. c4evaspeaks.com