If you are talking about Underworld evolution. That thing has got a boat load of "bad structure protection". The way I was able to back it up sucessfully was using any dvd and 1 click. All i did was to rip the dvd using any dvds built in ripper. This destroyed the protection. Then i used 1 click to do a movie only back up of the ripped ts file. Worked like a champ. Good Luck
PS: I could not back up directly from the dvd, It gave me the same error you are experiencing. It had to be ripped with any dvd first.