Newly Burned Backup Discs Not Playing

Hello. I am having a strange problem. I have a modded Xbox 360 that has always been able to backup games just fine, however I have been making a lot of coasters lately and I can't figure out why. I have been burning them the exact same way I always have and all of the sudden all of the new game I burn will not work. I thought it might be the burner on my laptop so I tried my wife's laptop with the exact same out come. All of the new burns don't work but all of the old ones still work flawlessly. I am going crazy trying to figure this one out. Please somebody help. Also it is a Samsung drive not to sure which ixtreme version it is but I would assume that it is 1.4 since it was modded just a couple month ago. Thanks.