Hi there.
When you preview web pages containing iframes that drag in information from the web, the frame displays as filled with unicode characters (instead of the programmed content).
You can see this by viewing this email in textmate (cntrl-cmd-E). Compare that to what you get if you view the email in safari (you can't just view, as it will have a .mail extension - reveal in finder and toggle this to html then double click.
<iframe src="http://rcm.amazon.com/e/cm? t=thewizardsoft-20&o=1&p=8&l=as1&asins=B000BW7QWW� 38;fc1=000000&IS2=1&lt1=_blank&lc1=0000ff&bc1=ffffff &bg1=ffffff&f=ifr" style="width:120px;height:240px;" scrolling="no" marginwidth="0" marginheight="0" align=right frameborder="0"> </iframe>