For anyone looking to do one of these videos and specifically, planning to use iMovie to make it - I thought I would share what I found after putting together our latest vacation video last week (which - shameless plug - you can see here:
http://www.youtube.com/watch?v=CNrQFbP_D20).
The problem with this video is that there is phantom audio showing up between about 2:00 and 2:30. This audio is not there when I watch in iMovie, where I assembled the video. Just when I export to DVD or YouTube. To make things extra weird, the audio is not from any part of my movie - it's from raw footage clips in my library that didn't even make it into the movie.
The phantom music is from an iMovie glitch. In iMovie you have the option to fast-forward your footage to either a pre-set speed (I believe they offer 150%, 200%, and 400%) or you can select your own speed. I usually selected my own speed to make the clip fit the timing of my music. And if you watch my movie you'll see that I used a LOT of fast-forwarding.
It's using these oddball speeds (like 183%) that result in the glitch. If I'd just stuck with the pre-set speeds, I would have been fine. (The only other time I have fast-forwarded in iMovie, I did a simple, pre-set 200% that worked just fine.)
I don't think there is anything I can do to fix this. I have tried stripping out all audio and adding it back in, but the phantom music just shows back up in a different spot. I may just have to learn to live with it.
Or... as someone on an iMovie forum offered when I was searching for a solution... bite the bullet, and buy Final Cut Pro!
Hope this helps someone else avoid the same aggravation!