if dvd decrypter of DVD shrink is not "doing" one of the vob files it means that it is uncrackable or unreadable.
Download DVD43 -
http://www.dvd43.com/ - which is an added software which sits in the background and boosts dvd shrink/decrypters capability of cracking the code.
DVD Shrink will compress any dvd to 4.7gb or less. You can do it manually by remving menus, unwanted languages or you can ask it to do it automotically. Anything compressed under 55% may come out a little pixelated. 55% and above and you will get a crystal clear picture.
DVD Decrypter will copy all files from dvd to harddrive without compressing. Good for films 4.7 or less. Anything over, use Shrink. Use Nero Express to burn the discs. I have used Decrypter and Shrink and Nero for 2 yrs, and it has worked fine. You will find that some dvds just will not copy as the coding is to advanced.