switch ($ajaxAction) {
    case 'add_instance':
        $url = PMF_Filter::filterInput(INPUT_GET, 'url', FILTER_SANITIZE_STRING);
        $instance = PMF_Filter::filterInput(INPUT_GET, 'instance', FILTER_SANITIZE_STRING);
        $comment = PMF_Filter::filterInput(INPUT_GET, 'comment', FILTER_SANITIZE_STRING);
        $email = PMF_Filter::filterInput(INPUT_GET, 'email', FILTER_VALIDATE_EMAIL);
        $admin = PMF_Filter::filterInput(INPUT_GET, 'admin', FILTER_SANITIZE_STRING);
        $password = PMF_Filter::filterInput(INPUT_GET, 'password', FILTER_SANITIZE_STRING);
        $data = array('url' => 'http://' . $url . '.' . $_SERVER['SERVER_NAME'], 'instance' => $instance, 'comment' => $comment);
        $faqInstance = new PMF_Instance($faqConfig);
        $instanceId = $faqInstance->addInstance($data);
        $faqInstanceClient = new PMF_Instance_Client($faqConfig);
        $faqInstanceClient->createClient($faqInstance);
        $urlParts = parse_url($data['url']);
        $hostname = $urlParts['host'];
        if ($faqInstanceClient->createClientFolder($hostname)) {
            $clientDir = PMF_ROOT_DIR . '/multisite/' . $hostname;
            $clientSetup = new PMF_Instance_Setup();
            $clientSetup->setRootDir($clientDir);
            $faqInstanceClient->copyConstantsFile($clientDir . '/constants.php');
            $faqInstanceClient->copyLdapConstantsFile($clientDir . '/constants_ldap.php');
            $dbSetup = array('dbServer' => $DB['server'], 'dbUser' => $DB['user'], 'dbPassword' => $DB['password'], 'dbDatabaseName' => $DB['db'], 'dbPrefix' => substr($hostname, 0, strpos($hostname, '.')), 'dbType' => $DB['type']);
            $clientSetup->createDatabaseFile($dbSetup, '');
            $faqInstanceClient->setClientUrl('http://' . $hostname);
            $faqInstanceClient->createClientTables($dbSetup['dbPrefix']);
            PMF_Db::setTablePrefix($dbSetup['dbPrefix']);
            // add admin account and rights
            $instanceAdmin = new PMF_User($faqConfig);
            $instanceAdmin->createUser($admin, $password, 1);
            $instanceAdmin->setStatus('protected');
            $instanceAdminData = array('display_name' => '', 'email' => $email);