Why do I ahve slow motion sound when I convert with AutoGK?

Hi,can anyone help me?
I have ripped a dvd to my hard drive using DVD decrypter. This gives me a series of files which play fine on windows media player but are like nearly one GB each in size. I want to combine them all to one avi of about 700Mb.
However when I try to do this with autogk my sound comes out in super slow motion.

Interestingly if I choose the audio described audio track, and look at the preview, the audio plays fine.
Is this something to do with the settings I have when I try to convert, if so how do I change them?