DVD OK on computer, but burning the disc, it quits after first menu encoding.

I am trying to burn a disc with one movie on it. Have lower the quality to SD as suggested. But in trying to burn a disc (or save a disc image), after the first menu, it stops encoding and says "error during rendering/encoding. There was an error during rendering/encoding of the menus/slideshows. The burning process has been canceled. The dvd plays fine on the computer. Any suggestions? iDVD 7.1.2 Thanks, Roy