Sugestion: Upgrade your Fedora to the latest stable version by the built in update manager or follow the instructions on this site: http://fedoraproject.org
That's not the best way to install Firefox in a Linux distribution (like Fedora). You should have install it from the repository and not by downloading from that site.
Search in your system menu for an app called: "Add/remove packages", "Software Manager" or something like this. Then just search for Firefox by category or type in "Firefox" in search box. Then just install it to your system. It should work good then.