Please Help: Creating Baackup DVD's of originals

This thread is about the Toshiba Satellite P300-1FY. Click here to see full specs

Hi,
I was wondering If someone could help me out with this problem I have.
I purchase new and second hand DVD's and to make sure they last I copy them and store the originals away.
I use DVD Shrink to copy them and use Nero 8 to burn them.
Now, I have been doing this for a while. However untill recently, I upgraded my version of Nero and it now seems as though I cant backup my originals I purchase.
I have tested this by reburning one of my originals that I have burned previously and I know it worked fine before.
However now when I do it again It doesn't work on my DVD player it only works on my PC.
I have tried several methods to do this and they dont work on my dvd player.
I believe it is Nero, because I downloaded a free burning program and useing dvd shrink I still have the same problem.
I have done nothing differant to DVD shrink and It still copies my originals no worries. It's the burning software I believe.
Is there something anyone can recommend to me to try. As I am not sure wat else to use considering I have been doing this for a while and this only started since I upgraded Nero.
Any recommendations would be good cause I'm not sure wat else to do?
Cheers.

Don't use Nero 8 with DVD Shrink. They are not compatible.
You can use Shrink, close and then open Nero for burning. Or better yet, you can use ImgBurn to burn to disc.
Either way, post your burn log. This will give a lot of information on what you can do to improve your burns.