PHPMailer: invio mail

[Gab-81]

Sto provando ad usare PHPMailer per implementare la mia mailing list...ottengo però questo errore:

Mailer Error: Language string failed to load: recipients_failed

Il codice per l'invio è il seguente:

/* Send an email to the subscribers */
function send_email($title, $content) {
    $mail = new PHPMailer();    // Create a PHPMailer object
    $mail->IsSMTP();    // set mailer to use SMTP
    $mail->Host = SMTP_HOST;    // specify main and backup server
    $mail->Port = 587;
    $mail->SMTPAuth = SMTP_AUTH;    // turn on SMTP authentication
    $mail->Username = SMTP_USERNAME;    // SMTP username
    $mail->Password = SMTP_PASSWORD;    // SMTP password
    $mail->From = MAIL_FROM;    // Sender
    //$mail->FromName = MAIL_FROM_NAME;    // Sender name
    /* Get all subscribers */
    $subscribers = db_get_all_subscriber();
    for($cnt = 0; $cnt < count($subscribers); $cnt++)
        $mail->AddAddress($subscribers[$cnt]['email'], $subscribers[$cnt]['name']);
    $mail->WordWrap = 50;    // set word wrap
    $mail->IsHTML(true);                                  // set email format to HTML
    $mail->Subject = $title;
    $mail->Body    = '<h1>'.$title.'</h1>'.$content;
    if(!$mail->Send()) {
   echo "Message could not be sent.";
   echo "Mailer Error: " . $mail->ErrorInfo;
   exit;
    }
    echo "Message has been sent";
} 

Qualche idea?
Grazie a tutti