错误：“无法实例化邮件功能”

Question

我正在使用Windows。当我尝试使用php邮件发送邮件。它返回“无法实例化邮件功能”。它是一些许可问题还是代码有什么问题？谢谢！

<?php   
    require_once("class.phpmailer.php");//location is correct
    require_once("class.smtp.php");//location is correct

    $to_name = "Good Better";
    $to = "sending@example.com";
    $subject = "Mail Test at ".strftime("%T", time());
    $message = "This is a test.";
    $message = wordwrap($message,70);
    $from_name = "My Name";
    $from = "myacc@example.com";


    $mail = new PHPMailer();


    $mail->FromName = $from_name;
    $mail->From     = $from;
    $mail->AddAddress($to, $to_name);
    $mail->Subject  = $subject;
    $mail->Body     = $message;

    $result = $mail->Send();
    echo $result ? 'Sent' : $mail->ErrorInfo;

?>