I have installed WOT as a firefox plugin and it wat not working. The only thing that I could read was "Data not available" (seen when mouse stayed for a while on the WOT object).

Reason: WOT was unable to ask me for its EULA.

How I got this out: WOT installed on another profile was working fine and have showed me EULA dialog screen. Later it was only tracking differences in the configuration.

Solution:
enter "about:config" (without " signs) in the address bar and press enter. Now enter filter "weboftrust.eula_accepted" (or just scrool to find it) and change its value to "true".