Help in CONTACT FORM

**Hi i’ve pasted it below, plz help me …i cant let my website run without this form:

THIS CODE IS ON THE FIRST FRAME**

stop();
send_mc._visible = false;

send_btn.onRelease = function() {
	my_vars = new LoadVars();
	my_vars.sender = name_box.text;
	my_vars.email = email_box.text;
	my_vars.subject = subject_box.text;
	my_vars.user = user_box.text;
	my_vars.message = message_box.text;
	if (my_vars.sender != "" and my_vars.email != "" and my_vars.subject != "" and my_vars.user != "" and my_vars.message != "") {
		my_vars.sendAndLoad("mailer.php", my_vars, "POST");
		send_mc._visible = true;
	} else {
		error_clip.gotoAndPlay(2);
	}
	my_vars.onLoad = function() {
		gotoAndStop("sucess");
	};
};
email_box.onSetFocus = subject_box.onSetFocus = message_box.onSetFocus = name_box.onSetFocus = user_box.onSetFocus = function () {
	if (error_clip._currentframe != 1) {
		error_clip.gotoAndPlay(6);
	}
};

THIS IS THE PHP CODE THAT IS “mailer.php”

<?php 

$subject = $_REQUEST["subject"]; 
$message = $_REQUEST["message"]; 
$sender = $_REQUEST["sender"]; 
$email = $_REQUEST["email"]; 
$user = $_REQUEST["user"]; 


$full_message = $_SERVER['REMOTE_ADDR'] . "

" . $message; 
$message= $full_message; 

$subject = "Contact Form "; 

if(isset($message) && isset($subject) && isset($sender)){ 
    mail("designursiter@yahoo.com", $subject, $message, "From: $sender"); 
}?>

**what i needs is when i press send it must send all the 4 details it comes blank in my email…

thx…a million in advance**