Maybe the extension's author can answer that. Usually there is a support link on the download page on the Add-ons site. On another subject, the forum software detected your Firefox as version 15. Is that correct? Version 15 is not secure; Mozilla discloses [https://www.mozilla.org/security/known-vulnerabilities/firefox.html security flaws] after each new release. Is something holding you back from upgrading to Firefox 26? Please let us know so we can suggest solutions or workarounds. If Help > About Firefox shows Firefox 26.0, you may need to clear the preference that is misreporting your version number. See: [[Websites say that Firefox is outdated or incompatible even though it's the latest version]].