If you are trying to make an exact copy of your dvd, without compression, here are the steps to use. First, start up AnyDVD and let it run in the background. Insert the dvd into your drive and let AnyDVD analyze the disk and break encryption. Now, right click the little fox icon for AnyDVD down in the bottom right of your screen, and then click Rip Video DVD to Harddisk...
This will put the entire movie on the hard drive in file format, minus only the encryption.
Now, the most important part. Buy Verbatim brand double layer disks. Do not substitute anything else.
Download a free burning program called ImgBurn. It is the best for burning double layer dvds. You can find it here: www.imgburn.com
Follow this guide for burning the dvd-video you ripped to the hard drive onto your new Verbatim brand double layer dvds: http://forum.imgburn.com/index.php?showtopic=1780
Set the burning speed in ImgBurn to 4x.