Choppy Transcode

I am new to ripping and am having problems.  I was trying to backup one of
my DVD's (The Gambler) and the transcode is choppy.  It plays frames slow,
then plays them fast.  There is actually a rhythm to it.  Half second slow,
half second fast, half second slow, half fast, etc.

Video and audio remain in sync throughout the movie.

Details:

Ubuntu 9.4
dvd::rip 0.98.9

NTSC video
xvid codec
50 Keyframes
29.970 framerate
Smart deinterlacing
By Target Size 1 x 700MB

clip and zoom:  Autoadjust, Medium Frame Size, HQ Resize

Any thoughts on what to try?

Thanks,

/em