PHP ile bir scriptte sorun nerede?

 
  $tireqty = $_POST['tireqty']; 
  $oilqty = $_POST['oilqty']; 
  $sparkqty = $_POST['sparkqty']; 
  $find = $_POST['find']; 
  $adress = $_POST['adress']; 
  	 
  $DOCUMENT_ROOT = $_SERVER['DOCUMENT_ROOT']; 
  $date = ('H:i, jD F'); 
   
  $totalamount = 0.00; 
  $outputstring = $date.'\t'.$tireqty.' tires \t'.$oilqty.'oil \t'.$sparkqty.' spark plugs \t\$'.$totalamount.'\t'. $adress.'\n';  
   
  //ekleme için dosya aç 
  	$fp = fopen("$DOCUMENT_ROOT/../orders/orders.txt", 'ab'); 
  	if (!$fp) 
  	{ 
  		echo '
Your order could not be processed at this time '.'Please try again later
'; 
  		exit; 
  	} 
  	 
  //dosyaya yaz 
  	fwrite($fp, $outputstring, strlen($outputstring)); 
  //dosyayi kapat 
  	fclose($fp); 
  	echo '<p>Order written</p>'; 
   
  

$fp = fopen("$DOCUMENT_ROOT/orders.txt", 'ab');