There are some issues throughout the scene with what sounds like static/interference, it lasts for only a couple of seconds when it occurs. I'm not sure how best to describe it but it's noticeable from the start so it won't be hard for you to identify and hopefully rectify.
Edit - Okay this is weird, the sound issue I noticed earlier was while watching it via stream. I just downloaded the file to my desktop and this issue is gone, it's been replaced however with a complete cutting out of the audio in certain places. If I stop the file and play from the start the audio is fine, then it hits a section that knocks it silent again, perhaps the interference parts from the stream. Very strange, is anyone else noticing this ? This is the mp4 vga version btw, yet to try the 720p.