Rated 3 out of 5 stars

Opens iTunes, but does not provide search results. FF 4.0. iTunes Will make rating 5 stars if fixed.

Hi chillgreg, I just checked iTunes Search with FF 4.0 and iTunes 10.2.1 on Mac and Windows and it worked fine, found an old Windows install of, tried that with FF 4 and it worked fine too. Upgrading to 10.2.1 couldn't hurt, I'd start with that.
Could you also try "Restart with Add-ons Disabled" from the Help menu and then try iTunes Search?
If that works, you have an add-on installed that's interfering with things. Start Firefox normally and begin disabling add-ons one at a time, restarting, and testing the search until you've found the culprit.

Ghostery is known to cause issues with iTunes Search, there may be other add-ons that are problematic.
If you find one, I'd be interested to know ;)