[brentk]

Others have made suggestions, so i will just add one to the list:

dvdfab

i use dvdfab and dvd decrypter and have never not been able to convert a dvd, i usually rip 3-5 dvds at a time and use handbrake to convert all of them at once, but a few times i had to use dvdfab to convert strait to mp4 format since none would rip the dvd.

good luck.

out of curiosity what dvd are you having problems with? thanks.