Probably Has something to do with the page location in the Url. If you have the option to choose URL relative, please do so.
If you have disabled cookies in your browser, the browser will not know how to react to the template.
Allready tryed to change the cookie settings in Firefox? You can do this in the private section in options fore Firefox.
(If this is the reason I would choose another kind of template.)
Did you also try a new update for Firefox. It can make a difference some times.