I just installed Wordfence Security 2.0.7 on my local WordPress installation (I test things out on a locally hosted install before trying them on my "real" server). I got this message upon activating the plugin:
Plugin could not be activated because it triggered a fatal error. Error fetching free API key from Wordfence: We could not fetch data from the API when calling 'get_anon_api_key': Array
Any thoughts about what might be going on?