private function catchWarning($errno, $errstr, $errfile, $errline)
    {
        $this->setError(array(
            'error' => "Connecting to the POP3 server raised a PHP warning: ",
            'errno' => $errno,
            'errstr' => $errstr,
            'errfile' => $errfile,
            'errline' => $errline
        ));
    }