Error opening DVDs with DVD Shrink

I am a complete newbie with respect to DVD copying, but very computer literate otherwise. I just downloaded DVD Shrink (both 2.3 and the 3.0 Beta 5). I have 2 DVD drives, a Toshiba SD-W2002 DVD-RAM, and a Memorex DualFormat.

I have tried a number of different combinations (both drives, with and without AnyDVD, including Safe Mode, with the following movies:

The Right Stuff Special Edition
The Three Musketeers
Father of the Bride

Each time, I get the following error message when I try to open the disk:

DVD Shrink encountered and error and cannot continue this operation.

CDvdCSS: Read Failure

The reason is: Unknown.

I tried searching on DVD Shrink open error and found nothing useful. Does anybody know what the problem might be?

Thanks in advance.

You might try using DVDDecrypter to rip the files to the hard drive (use file mode). Then use Shrink to get them to the size you need to burn onto the disk. Sometimes Shrink cannot read a disk, usually because it is scratched, but not always. DVDDecrypter is a good alternative ripping program.

Here are some other things to look for:
http://forum.digital-digest.com/showthread.php?s=&threadid=25577