Part of video is perfect, part is completely trashed

[Solidus]

i'm trying to rip The Big Hit. every time, the first 59 minutes are perfect, nice video quality and the audio is in perfect sync. after 59 minutes it gets interlaced, audio is completely out of whack, and it sometimes has a wierd slow motion effect. i've tried several different encoding methods, including flask, dvd2avi, and mpeg2avi, and all of them have the same problem. any ideas?