Formulaire mail sur flash - l'envoie fonctionne 1 fois sur 2 ?!

import fl.managers.StyleManager;

StyleManager.setStyle("textFormat", new TextFormat("Segoe Script", 16, 0x000080));
const SENDING:String   = "Sending";
const SENT_SUCCESS:String = "Successful";
const SENT_FAILED:String = "Unsuccessful";
var tmr:Timer;

function resetTextFields():void
{
	name_txt.text  = "";
	email_txt.text  = "";
	message_txt.text = "";
}

function resetContactForm():void
{
	submit_btn.enabled = true;
	feedback_mc.visible = false;
	clearErrors();
}

function afterTmrWait(evt:TimerEvent):void
{
	tmr.stop();
	tmr.removeEventListener(TimerEvent.TIMER, afterTmrWait);
	resetContactForm();


	removeEventListener(Event.ENTER_FRAME,btnRetourSousdoss);
	gotoAndPlay(10);
}

function validateEmail(str:String):Boolean
{
	var pattern:RegExp = /((\w|[_.\-])+@((\w|-)+\.)+\w{2,4}+)|^$/;
	var result:Object = pattern.exec(str);
	if (result == null)
	{
		return false;
	}
	return true;
}

function submitForm(evt:MouseEvent):void
{
	clearErrors();

	var passChecks:Boolean = true;

	if (name_txt.text.length < 1)
	{
		nameError_mc.visible = true;
		passChecks = false;
	}
	if (! validateEmail(email_txt.text))
	{
		emailError_mc.visible = true;
		passChecks = false;
	}
	if (message_txt.text.length < 1)
	{
		messageError_mc.visible = true;
		passChecks = false;
	}

	if (passChecks)
	{
		submit_btn.enabled = false;
		feedback_mc.visible = true;
		feedback_mc.gotoAndStop(SENDING);

		var urlVars:URLVariables = new URLVariables();
		var urlReq:URLRequest  = new URLRequest("send_email.php");
		var ldr:URLLoader   = new URLLoader();

		urlVars.name = name_txt.text;
		urlVars.email = email_txt.text;
		urlVars.message = message_txt.text;
		urlReq.data = urlVars;
		urlReq.method = URLRequestMethod.POST;
		ldr.addEventListener(Event.COMPLETE, serverFeedback);
		ldr.load(urlReq);
	}
}

function serverFeedback(evt:Event):void
{
	var ldr:URLLoader = evt.target as URLLoader;
	var urlVars:URLVariables = new URLVariables(ldr.data);

	if (urlVars.result == SENT_SUCCESS)
	{
		feedback_mc.gotoAndStop(SENT_SUCCESS);
		resetTextFields();

		tmr = new Timer(3000,1);
		tmr.addEventListener(TimerEvent.TIMER, afterTmrWait);
		tmr.start();
	}
	else if (urlVars.result == SENT_FAILED)
	{
		feedback_mc.gotoAndStop(SENT_FAILED);
		submit_btn.enabled = true;
	}


}

function clearErrors():void
{
	nameError_mc.visible = false;
	emailError_mc.visible = false;
	messageError_mc.visible = false;
}

submit_btn.addEventListener(MouseEvent.CLICK, submitForm);

resetTextFields();
resetContactForm();

<?php

$emailTo = "monEmail@truc.fr";
$name = $_POST["name"];
$emailFrom = $_POST["email"];
$message = $_POST["message"];
$subject = "Site Web";

if( !empty( $_POST ) ) {
	$body  = "Name: " . $name . "\n\n";
	$body .= "Email: " . $emailFrom . "\n\n";
	$body .= "Message:\n" . $message;
	$body  = wordwrap($body, 70);
	$header = "From: " . $emailFrom . "\nReply-To: " . $emailFrom. "\n\n";
	
	if( mail( $emailTo, $subject, $body, $header ) ) {
		echo( "result=Successful" );
		
	} else {
		echo( "result=Unsuccessful" );
	}
}
?>