http://forums.avg.com/us-en/avg-free-forum?sec=thread&act=show&id=171434

Safe Search extension is not compatible with Firefox 6.0

Mozilla has released their new Firefox 6.0 browser for public. Unfortunately, the AVG Safe Search extension is not compatible with this browser version yet (example screenshot). We found some glitches during our internal testing and developers are working on rectifying them. A new AVG program update will be released as soon the support is fully implemented. You may also notice some other Firefox extensions are not compatible as the Firefox development cycle is quite rapid.

Please rest assured you are still protected by AVG even if you have already upgraded to Firefox 6.0. The AVG Active Surf Shield component is still checking all data and will prevent you from accessing malicious content even though search results verdict icons are not available temporarily.

The Java console extension that Java installs in Firefox is actually not needed unless you are doing some Java development and it is also not needed for the Java Plugin (in Tools->Addons->Plugins) to work

Many thanks. I have noted the contents of your reply and await further developments.