go to www.dvddecrypter.com and download the program DVD Decrypter. Then run it, extract the VOBs (6 gigs) to your hard drive temporarily. Then just drag and drop those files to dvd burner program of choice and burn. delete temp vobs from hdd.
just like Gus K said, u cant just rip the vob's off the dvd disc and burn it and then expect it to play. u have to re-create the audio_ts and video_ts folders and a couple of other files and burn those to yr dvd-r.
take a look at www.vcdhelp.com at the left and ull see a section for DVD Rip, go there and you'll find everything you need.