The menu doesn't even work!
your menu doesn't work at all in NS6. To fix this, you must implement The DOM way of hiding and showing elements. You're going to have to put in another thing in your if else statement:
ns6=(document.getElementById) ? true:false
else if (ie4)
} else if (ns6)
To hide it, the visibility property should be "hidden"
Since i don't actually have access to your server, plus i don't really have the time, i can't test and replace the include by myself.
Computers are simple for the complex mind, yet complex for the simple mind