Email/PHP Form Not Working

I am trying to make an e-mail form that is integrated into Flash. To do this, I have been using the tutorial on this site at: http://www.kirupa.com/developer/act…h_php_email.htm and have followed it pretty much to the t. However, when I test the form out at http://www.terrieades.com/in_progress/pda/largered.html (click on “Mail”), it never alerts me that the form has been sent, which I have set it up to do. Since I followed the directions so closely, I’m not sure if this is a problem with the AS, or the PHP file.

Here are both:

http://www.terrieades.com/in_progress/pda/Flash Presentations/pda_largered.zip (FLA file)

<?php
$sendTo = " . $_POST["to"] . ";
$subject = "E-mail from Future PDA";


$headers = "From: Future PDA Demo";
$headers .= "pda_demo@terrieades.com";
$headers .= "Reply-To: pda_demo@terrieades.com";
$headers .= "Return-Path: pda_demo@terrieades.com"];
$message = $_POST["message"];


mail($sendTo, $subject, $message, $headers);
?>

Thanks for any help, and thanks for the great tutorial! (I have actually gotten it to work on another site before, which is why I wanted to come back to it.)