I think you have to have either a chip or a tool device of some kind to make the game backup discs playable.
You will need a modded system & either/or swap/coder discs.
I have not used DVDfab, so I don't know about that, but DVD Decrypter will do just fine, ISO read. Follow the link -
Also, older ps2 games are CD, most newer titles are DVD's, so you need to use different programs for both.
It is not that hard to do, & remember to use good grade media such as Verbatim or Taiyo Yuden!
Hope this helps!