Récupération de fichiers impossible

$id = $_POST['id']; $name = $_POST['name'];
$type = "";
switch(strrchr(basename($name), ".")) {
  // fonction permettant de definir le content-type
}
$db_name = requete de recuperation du filename;
$source = $db_name[0];

header('Content-Type:' . $type);
header('Content-Length:'.filesize($name));
header('Content-Disposition: attachment; filename=' .$name);

readfile($source); 

header("Content-Description: File Transfer");

<?php
header ("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header ("Last-Modified: " . gmdate("D,d M YH:i:s") . " GMT");
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header("Content-Type: application/force-download");
header('Pragma: no-cache');
header ("Content-type: application/zip");
header ("Content-Disposition: attachment; filename=\"".$fileName."\"" );
header("Content-Length: ".filesize($fileName));
readfile($fileName);
?>