Copied Movie more than one time?

I have an Optorite DVD rewriter (DD1603) my problem is that when I copy any movie with any software (DvdShrink, CloneDVD, etc) it makes a perfect copy one time only. If I try to copy it again from the one is already a copy those softwares wont do it. I dont know where is the problem since I belive once you copy any movie and have it backed up you can keep copying it many times more or not?

I recently needed to make a backup of a dvd movie that I had burned (the original having gone kaput some time back) and which was starting to get scratched etc. One pointer if you try to make a copy of a copy on a different computer to which you made the original copy, you will be more likely to get problems if that’s your case. It should work fine though. Have you tried dvd decrypter to rip then do an iso and burn with same program?