Does your version of Linux support Firefox 3.0+ versions? http://www.mozilla.com/en-US/firefox/system-requirements.html Most Linux distros that came with Firefox 2 don't have the correct packages for 3.0+ versions, usually at least the GTK package needs to be updated. Here's the Linux installation intructions. https://support.mozilla.com/en-US/kb/Installing+Firefox+on+Linux https://help.ubuntu.com/community/FirefoxNewVersion/MozillaBuilds