Okay I'm seeing a bizarre situation where the tweet button inserts an iframe into your content as below:
<body data-twttr-rendered="true">
<div align="center">
<iframe id="rufous-sandbox" scrolling="no" frameborder="0" style="display: none;">
<!DOCTYPE html>
<html>
<head>
<script>
try { window.parent.document; }catch (e) {document.domain="www.example.com";}
</script>
</head>
<body></body>
</html>
</iframe>
</body>
(example.com repaces actual domain in code above)
I was looking at the page in Firebug to try and improve the layout a bit when I noticed this.
Testing in Opera Dragonfly and IE Developer tools revealed the same behaviour.
Removing the Tweet button caused the page to render as expected without the iframe.
