We have discovered and fixed an issue in Worldspace FireEyes that affected new users and made it impossible for them to use the product at all. The issue also caused Firebug to stop working. The fix has been deployed to the download site and can be downloaded from: http://fireeyes.dequecloud.com/fireeyes_download.php
To check that you have the correct version installed go to Tools->Add Ons from within Firefox. You should see "Worldspace FireEyes 0.3.1" as the installed version of FireEyes. If you do not see this, then you will need to download the latest release.