We are looking into the video errors this morning. I checked the site out on my Mac with both Firefox 0.8 and Safari 1.2 and have the same experience. Two errors per video pop up. The interesting thing is that homepage is the only one that does it for me. If you go to: http://channel9.msdn.com/ShowPost.aspx?PostID=74 There are no errors and it plays fine. I have the devs looking into it and we will post when it is fixed.