When you say the menu doesn't work, what is happening exactly? What displays and what doesn't display? I take it this is just a problem for Kubrick, and in other themes the menu works ok. Do you notice any other problems with the Kubrick theme?
I've got to pick this up again. I went over to http://themes.tikiwiki.org/tiki-index.php?page=Kubrick and the menus were not working there either.
The menus are visible, but the hover and link does not work. I thought this was just my setup/installation as you suggested, but now I wonder whether it is my FF3 (Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:22.214.171.124) Gecko/2008092417 Firefox/3.0.3) .
Maybe a plugin? Pluggins in my FF3 include: yslow, firebug1.2.1, Fast Video Download 1.6.1, Flashgot 126.96.36.199, Web Developer 1.1.6, editcss0.3.7, Colorzilla 2.0
Has anyone else noticed this peculiarity?