If IE has a silver lining, it would be its intolerance of orphan tags in HTML. That is the first thing to check when experiencing problems with IE. The HTML really should be squeaky clean. The css works better, too.
The following tags do not have corresponding open tags:
Line 137 has an unmatched </div>
Line 331 has an unmatched </span>
Line 341 has an unmatched </span>
Line 371 has an unmatched </span>
Line 417 has an unmatched </span>
I doubt that css within the body of the page is a good idea, either.
I do not know if the above findings will help or not, but it is the right place to start before tinkering with the css.