You are probably running into a copy protection that is too new for DVDDecrypter to handle on its own. However, AnyDVD should be able to break the encryption for you and let DVDDecrypter rip the movie to the hard drive with no problems. Let AnyDVD run in the background as you use DVDDecrypter.
Have you tried the built-in ripper that comes with AnyDVD? Right click on the Fox icon at the bottom right, then hit Rip Video DVD to Harddisk. That is another option.
Once on the hard drive, Videora should be able to convert for you.