Did you follow a particular guide to using DVD Decrypter? Personally I use SMARTRIPPER and haven't had any real problems. You can either burn using ISO or UDF/IFO , of these two choices I use UDF/IFO which needs all .BUP .IFO & .VOB dragging to VIDEO_TS folder then burnt (using NERO in my case). Hope I've helped some...
i just used the guide that was attached to this site and it said that there should be a .IFO and a .DVD file. nothing about .MDS
You either want an .ISO if your going to burn from a created image. For UDF/IFO you want a folder full of .BUP .VOB & .IFO files.