All the pages below refuse to render using IE8, but work fine with Firefox 3.6.3. The page returns the top half of the page down to the border below the page title and then gets stuck waiting...
In IE8 you have developer tools. Press F12 to see it. There (on the top of this developer panel) you can play with Document Mode and Browser Mode. Try to change it and refresh page. Tell me what happens
Interestingly the Demo admin site does work after a long delay the page appears. 10 seconds approx. This delay is worse with FireFox 20 seconds approx.