DVD FAB Locks Up Computer

DVD Fab keeps locking when trying to convert a dvd to ipod format. This last time was when I was trying to rip down Family Guy Season One Disc One. It seems to happen only on the last episode on the disc of TV Show dvds. It gets to the last second or two of the last episode and then freezes up the computer. I was wondering if anyone else has experienced this problem or if anyone can shed any light on this for me.
Thanks!!