Maybe i am just up too late, but If you click "about us" then start clicking the nav links (if you don't close it) it works just fine...however, when the page loads, ONLY the about us link works correctly.
Here is the draft up and running: http://www.pixeltweaks.com/ground_zero
I am sure it is something simple that i am just not able to pick up on, perhaps one of you more seasoned vets can be of assistance.
Thanks guys.