Having problems with my sony dvd rw-d22a not burning properly anymorer

Hi I am having problems getting my sony dvd RW-D22A to burn properly.I am trying to back up some of my own Dvds.I have a program to remove the copy protection.and i am using the same writing program i have always used.It use to burn perfectly but all of a sudden now it burns but when i go to play on my dvd player it pictalates and freezes.when i go to remake an image of the back up the disk just comes up like a blank disk…how can i correct this problem and resume back to burning good backup disks again .i am useing the same white printable dvds i have always used …If anyone has any suggestions on what i can do to solve this problem i would be greatful…thank you