The li for the left navigation is starting below the content in the right column. IE 7 and FireFox 3 both display the li where the author clearly intended it to be.
Created attachment 24151 [details] Screenshot of IE 7, FF 3, Safari 3.1 and Chrome Beta The screen shot clearly shows the difference between IE7, FF3 and Safari 3.1
Duplicate of bug 28350. (I'm really curious how you triggered this nearly a year before anyone else hit it, though.)
*** This bug has been marked as a duplicate of bug 28350 ***
Closing this because it is a resolved duplicate of 28350.