无法使用hook_mail在Drupal 7中发送电子邮件

Question

请解释我在哪里有问题，我尝试发送电子邮件但是，它不起作用。我看到的一个错误是＆＃34; 500内部服务器错误＆＃34;，在firebug控制台中。我使用AJAX访问执行drupal_mail（...）的函数。请帮帮我一个人解释wtf它不起作用....提前感谢。

    function duels_create_duel(){
       $params = array();
                $params['subject'] = "Theme";
                $params['message'] = "Test message";
                $params['body'] = array();
                $params['body'][] = "Test message1";
                $params['body'][] = "Test message2";
                $params['body'][] = "Test message3";
                $params['headers']['MIME-Version'] = '1.0';
                $params['headers']['Content-Type'] = 'text/html; charset=UTF-8; format=flowed';
                $params['headers']['Content-Transfer-Encoding'] = '8Bit';
                $params['headers']['X-Mailer'] = 'Drupal';                    
                drupal_mail("duels", "duel_start_op", "viktor.s@glyanec.net",       language_default(), $params);
                print json_encode(1); exit;
    }
    duels_create_duel();

    function duels_mail($key, &$message, $params){
        switch($key){
            case 'duel_start_op':
                if (isset($params['subject'])) {
                    $message['subject'] = str_replace(array("\r", "\n"), '', $params['subject']);
                }
                if (isset($params['body'])) {
                    $message['body'][] = $params['body']; 
                }
                if (isset($params['headers']) && is_array($params['headers'])) {   
                    $message['headers'] += $params['headers'];
                }
//this one i use just for checking.
                mail('viktor.s@glyanec.net', 'test', "Failed"."\r\n" . print_r($message, TRUE)); 
            break;
            case 'duel_start_u':
            break;
            case 'duel_rejected':
            break;
        }
    }