Loading php output into flash to determine message

Hi there,

I am using the following tutorial to create a php message page, however, even in their example, I cannot get the php echo function to send the output to the dynamic text fields: http://www.sephiroth.it/tutorials/flashPHP/email/index.php.

Here is the button code to send the php variables and attempt to capture the php echo of either "sent" or "error"

on (release) {
    //    Now import the variables we
    //    need to send in this movie clip
    sender_mail = _root.Semail.text
    sender_name = _root.Sname.text
    sender_subject = _root.Ssubject.text
    sender_message = _root.Smessage.text
    //    all the vars we just imported
    //    will be sent via POST method now
    loadVariables("sendmail.php",this,"POST");
    //    and when receives the answer from
    //    the server...
    this.onData = function()
    {
        //    ok, next frame
        _root.nextFrame();
        if(this.output=='sent')
        {
            // in case of success
            _root.errTitle = 'Thank You.';
            _root.errType = "Your message has been succesfully sent.";
        } else {
            //    else
            _root.errTitle = "Error!";
            _root.errType = "Attention, an error occurred. Please try again later.";
        }
    }
}

Here is the php which should echo the "sent" or "error"

<?
if(!empty($HTTP_POST_VARS['sender_mail']) || !empty($HTTP_POST_VARS['sender_message']) || !empty($HTTP_POST_VARS['sender_subject']) || !empty($HTTP_POST_VARS['sender_name']))
{
     $to = "email@website.com";
     $subject = stripslashes($HTTP_POST_VARS['sender_subject']);
     $body = stripslashes($HTTP_POST_VARS['sender_message']);
     $body .= "\n\n---------------------------\n";
     $body .= "Mail sent by: " . $HTTP_POST_VARS['sender_name'] . " <" . $HTTP_POST_VARS['sender_mail']  . ">\n";
     $header = "From: " . $HTTP_POST_VARS['sender_name'] . " <" . $HTTP_POST_VARS['sender_mail'] . ">\n";
     $header .= "Reply-To: " . $HTTP_POST_VARS['sender_name'] . " <" . $HTTP_POST_VARS['sender_mail'] . ">\n";
     $header .= "X-Mailer: PHP/" . phpversion() . "\n";
     $header .= "X-Priority: 1";
     if(@mail($to, $subject, $body, $header))
     {
          echo "output=sent";
     } else {
          echo "output=error";
     }
} else {
     echo "output=error";
}
?>

The email does send fine, but it does not show the message which lets the user know the status of the message.  Any ideas?  There is a link to download the .zip file of the tutorial - I have attached it here.