You has a div class="columns" inside a div class="wrap" inside a div class="content". The two divs within the div class="columns" are both floats.
I believe the div class="columns" will inherit the position: relative style from the div class="content".
The bug fix would suggest that giving the .columns selector in style.css a style zoom:1 should resolve the problem.
I have tried to open it, though it's very slow, but i open it fanally and display test normal in IE 8, then i try it in firefox, it doesn't display!
I don't know where the problem come from the site or the broswer
However I found this bug in IE8 not IE6 and your reference site also note that this bug has been suppressed since in IE7.
I also try to add zoom:1 in .columns but it doesn't help
the page are made from around 10 included files so it might be slow in some computer.
It display fine in my FF 3.6 and chrome.
The problem in IE8 is in the middle content, if you scroll down to 10th paragraph you will see some gap.
When you hover mouse above the gap the text will display.
The text can also display by select the text.
IE8 have a lots of bug that's why i does not use IE8 to open website .I think you try to need edit text live with IE8 its live web editor tools available check it.Its really tension work to set your website on IE.
Sorry for going on about the accordion. Everything I do seems to point to it being the cause.