@ Zaq!! Really sorry, i just realized the size of my stupidity when i made this statement!!!
You were right, the _Gr extension means Greece, and the original disc i own is a Region 2 (PAL) Dvd Disc for Greece & Italy. What are IFO's and where do i find them?? I guess they are file extensions, like VOB's???
Now to be more specific:
With DVD Shrink 3.2 & AnyDVD 184.108.40.206 I get this message:
"DVD Shrink encountered an error and cannot continue. Invalid DVD navigation structure"
With CloneDVD 220.127.116.11. I get this message:
"Cannot Open Disc. Data cyclic redundancy error"
With Nero 18.104.22.168b i get this message:
"Unable to read disc. Error At LBA 0"
That's all! Thank you in advance for your advice!