Hiya -- I'm having the exact same problem as mentioned here
YouTube vids on my page are on top of my shopping cart window. While your solution does indeed work, it only seems to work with the old way YouTube wants you to embed videos. The newer, easier way to embed YouTube vids is using iframes. Using iframes, you get simple, easy-to-manage code looking like this
<iframe width="560" height="315" src="http://www.youtube.com/embed/bYs3BWi9iXg" frameborder="0" allowfullscreen></iframe>
Is there a way to use iframes and still let the shopping cart on top of the YouTube windows? This would be VERY helpful. Thanks!!