backing up xbox 360 games problems

Hi guys

Ive had a problem recently with backing up xbox 360 games. All the old games i have done work fine but the new games lately dont work. Ive got the iso and the dvd file and im using img burn to back them. My media is verbatim dvd + r DL. When i put the dvd file in imgburn the title normally comes up with something along the lines of xg2dvd ntsc but lately it has been coming up with dvd-rom and when i put the games into my xbox it says play dvd then comes up with a white screen with the xbox 360 logo in the middle of it? Could this be my fimware on my console needs updating? im not sure what firmware its running at the moment? does my burner in my pc need updating as well? its a lite-on one. Any help would be appreciated thanx