Copied movies stutter and lock "please help"

I am using Clonedvd2 and anydvd. Movies burn and play well until about half way through the movie then it starts to stutter and eventually locks up. Will someone please help…???

Usually a sign of bad media or media that isn’t compatible with your writer. What type of dvd blanks are you using?

I am using Sony and memorex (both DVD-R). using several different brands of players. some hangup right away and other dont hangup until well into the movie but eventually they do.