fiddler,
It looks to me as if you are having doctype issues.
please read this http://www.alistapart.com/articles/doctype/ written by Jeffry Zeldman, who is considered by a lot of professional web developers to be the best web site engineer in the world.
You problem seem to me that your mark up file breaks when the easy embed template reapplies your mark up as a xthtml 1.0 file and not the html 4.0 that you made it. By the way you should really make sure that you have working mark up to begin with. When I looked at your template in the w3 validator I got 13 errors when I ran it. http://validator.w3.org/check?verbos...on%2Fshop.html

You should update you mark up to match the xhtml 1.0 transitional standard. because that is how zen cart tells you browser to parse it.