Flash script interact with php

Hey,

I making a mail form but get stuck on something, im having a flash script looking like this

on (release) { 
// create LoadVars(); Object
emailForm = new LoadVars();
// Attach vars to object
emailForm.totalName = firstName + " " +lastName;
emailForm.emailAddr = emailAddr;
emailform.adres = adres; 
emailForm.messageBox = messageBox;
emailForm.newvar = myComboBox.getValue();
//traces vars
trace (emailForm.firstName);
trace (emailForm.lastName);
trace (emailForm.emailAddr);
trace (emailform.adres); 
trace (emailForm.messageBox);
trace (emailForm.newvar);
// Send vars out with sendAndLoad
emailForm.sendAndLoad("viperMail.php",emailForm,"POST");
_root.contactClip.gotoAndPlay("thank");
}

And a php code like this

<?php 
$interest = $_POST["newvar"]; 
$comment = $_POST["messageBox"];
$EmailBody = "Keuze van workshop: $interest 
Message: $comment"; 
$sendTo  =  "[email="[email protected]"][email protected][/email]";
$subject  = "Inschrijving Workshop";
$headers  =  "From: " . $_POST["totalName"];
$headers .=  "<" .  $_POST["emailAddr"] . ">
";
$headers .=  "Reply-To: " .  $_POST["emailAddr"] . "
";
$headers .=  "Return-Path: " .  $_POST["emailAddr"];
$message  = $EmailBody;
mail($sendTo,  $subject,  $message,  $headers);
?>

I know how to ad a extra var in flash as you can see

emailform.adres = adres;
trace (emailform.adres);

But my question is: what must I put in the php then? to make it work correct?

Many thanks Michael