Ohh yes now I can see it... clearly. Your problem is pretty simple really.

It's just that you DON'T HAVE any menues there You only have the javascript file that refers to the menues, which do not exist. I couldn't see it with iexplorer firefox or whatever. Look a THIS thread I have posted a menu for the tutorial, there are some video tutorials as well. I have no idea about you saying you can view the menu in Internet Explorer since it's clearly seen you have items missing in the site's header. Besidesm the javascript is compatible with all browsers so it is odd you have this problem in FireFox.