Site displays diff in IE9 than IE8 today

I’m having problems trouble shooting the difference in display between IE8 (works fine) and IE9 for the site:
[url]http://www.exploreolympics.com/[/url]
Seems this problem just developed, both browsers had displayed the same two days ago.
In IE9 the right 2/3s (below the header) doesn’t seem to fit and is dropped down below the left 1/3 panel.
It seem that there should be sufficient room as I review the CSS… but I must be missing something.
CSS file is here:
[url]http://www.exploreolympics.com/style_sheets/main_styles3.css[/url]
Best wishes,
Eye for Video

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