…or check your "software sources" (don't know how they call it in English, but well, your package sources) and make sure you don't have any Firefox-related PPA, such as http://ppa.launchpad.net/mozillateam/firefox-next/ubuntu or http://ppa.launchpad.net/mozillateam/ppa/ubuntu.
Or maybe you're updating to Oneiric rather than Natty? Oneiric has Firefox 5.0 beta: https://launchpad.net/ubuntu/+source/firefox/ -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To view this discussion on the web visit https://groups.google.com/d/msg/google-web-toolkit/-/Nj8tZdUHqcwJ. To post to this group, send email to google-web-toolkit@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.