PHP Anhang per PHP senden, Fehler im Code?

<?php

if (!empty($_POST)) {
	// get the posted data 
	$name = $_POST['name']; 
	$adress = $_POST['adress']; 
	$telefon = $_POST['telefon']; 
	$mobil = $_POST['mobil']; 
	$fax = $_POST['fax']; 
	$email_address = $_POST['email'];
	$stelle = $_POST['stelle'];
	$arbeit = $_POST['optionsRadios'];
	$email_subject = "XXX"; 
	$attachment = chunk_split(base64_encode(file_get_contents($_FILES['file']['tmp_name'])));
   	$filename = $_FILES['file']['name'];
   	$boundary =md5(date('r', time())); 
   	$message = strip_tags($_POST['message']);
	
   	$to = 'xxx@xxx.de';

	// write the email content 
    $headers = "From: xx@xxx.de\r\nReply-To: xx@xxx.de";
   	$headers .= "\r\nMIME-Version: 1.0\r\nContent-Type: multipart/mixed; boundary=\"_1_$boundary\"";
	
	$message="This is a multi-part message in MIME format.

--_1_$boundary
Content-Type: multipart/alternative; boundary=\"_2_$boundary\"

--_2_$boundary
Content-Type: text/plain; charset=\"iso-8859-1\"
Content-Transfer-Encoding: 7bit

	--------------------------------
	--------------------------------
		
	Mitarbeit: 	$arbeit
	Stelle: 	$stelle
	
	Name: 	$name
	Adresse: 	$adress
	Telefon:	$telefon
	Mobil: 	$mobil
	Fax: 		$fax
	E-Mail: 	$email_address
	
	--------------------------------
	--------------------------------
	
--_2_$boundary--
--_1_$boundary
Content-Type: application/octet-stream; name=\"$filename\" 
Content-Transfer-Encoding: base64 
Content-Disposition: attachment 

$attachment
--_1_$boundary--";

}
?>

Content-Disposition: attachment; filename=\"$filename\"

$mail = new \Email();
$mail->attachFile($filename, 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
$mail->subject = $subject;
$mail->html = $htmlText;
$mail->text = $pureText;
$mail->sendTo($strSendTo);