The UK's largest independent broadband news and information site
Do you use NoScript?
If you use this Firefox add-on, you'll need to "Temporarilly allow all this page". You will need to do this twice for everything to work. Alternately, disable NoScript entirely until you are done with this site.
You can opt instead to view the simple test, which will give you a quick pass/fail for IPv4, IPv4+IPv6, and IPv6. IT will however offer little diagnostic information.