DVDShrink has not been updated for decryption in over six years, since development stopped for this program. There are dozens, perhaps hundreds of movies it cannot decrypt due to newer protections placed on commercial movies.
I suggest using DVDFab to decrypt and rip your movie. There is a free trial for the program, good for 30 days. While the trial lasts, you can also use it to compress the movie to fit a blank single layer dvd if you wish. Once the trial ends, there is a free section within it called DVDFab HD Decrypter which will continue to function as a decryption/ripping program. At that point you can rip problematic dvds with DVDFab, then compress with DVDShrink if necessary.
The only caveat to using DVDFab HD Decrypter to decrypt and rip your movies is that it will lag behind the commercial version on updates by six to eight weeks. But that is certainly better than six years! And it is the only free decryption option left that is still being updated that will rip to file format.