It should be possible to rip this dvd to the hard drive and make another copy. You can even add an empty Audio_TS folder if you like. Very few dvd players look for the audio folder as it is a legacy not utilized. The video and audio streams are combined in the Video_TS folder.
I don’t know if this dvd is copy protected, but you can use DVDFab HD Decrypter and try to rip to the hard drive. http://www.dvdfab.com/free.htm The free decrypter/ripping section will continue to work even after the trial for the main section expires.
Is your copy pressed or is it a burned disk? If it is a regular burned dvd it may be poor quality disk, or burned too fast for that particular media. I suggest getting some Verbatim 16x speed disks and burning them at 8x or 12x with your new copy.
You can use a free burning program called ImgBurn for this process…or use your regular burning program if it has an option for dvd-video. www.imgburn.com
And here is the guide for burning dvd video using ImgBurn: http://forum.imgburn.com/index.php?showtopic=4632
If you need AVI or Mpeg that is possible too. Very easy to get mpeg2 video out of dvds. Let us know.