I am having trouble with the audio also. I downloaded the new version 7.2. This version requires Windows Vista or XP. My problem is that I am still using W2K and am very happy with it.
All of the other videos seem ok. Well, I should say that I have just open the first video after the third and the audio is fine.
I would have expected a caveat saying that Windows XP minimum is needed for full compatibility.
Maybe there will be a work-around.