Web services

i have a xmlrpc web service that has NO parameters. It just does some stuff in the context of $USER (which it gets from the token) and returns a result. But no matter what, I always get 'Calling parameters do not match signature' - that old gem.

My externallib class' function is like this (the methodname in services.php is set correctly):

public static function completion_status () {
        global $CFG, $DB, $USER;
        require_once($CFG->dirroot ."/course/lib.php");
        $context = get_context_instance(CONTEXT_USER, $USER->id);
        self::validate_context($context);
        $rows = $DB->get_records('vw_completions', array('WPUsername'=> $USER->username)); // pull from a VIEW
        return $rows;
}

my parameters function looks like this:

public static function completion_status_parameters() {
        return new external_function_parameters(
                array()
        );
}

Every tutorial or forum post I've read so far dealing with this error talks about having some sort of mismatched property (int instead of string, etc). I can't seem to call a webservice without having any parameters, which I do not need.

In my test client I'm doing this since xmlrpc_encode_request REQUIRES a second parameter:

$post = xmlrpc_encode_request($functionname, array()); // empty array = no parameters
$raw = $curl->post($moodle . '/webservice/xmlrpc/server.php'. '?wstoken=' . $login_token, $post);