مشكلة في كود برمجي

لدي هدا الكود لكن لا أعرف أين الخطأ

<?php

if(isset($_FILES['upload_file']))

{

$name = $_FILES ['upload_file']['name'];

$type = $_FILES ['upload_file']['type'];

$size = $_FILES ['upload_file']['size'];

$error = $_FILES ['upload_file']['error'];

$tmpname = $_FILES ['upload_file']['tmp_name'];

for ($i = 0; $i < count ($tmpname); $i++) {

require("connect.php");

$charset = "AHfgG15Ds10MZD58N";

$code = '';

$length = 15;

for ($i = 0; $i <= $length; $i++)

{

$rand = rand() % strlen($charset);
$tmp = substr($charset , $rand , 1);
$code .= $tmp;

} $query = mysql_query("SELECT code FROM files WHERE code='$code'") or die(mysql_error()); $numrows = mysql_num_rows ($query);

while ($numrows !=0) { for ($i = 0; $i <= $length; $i++) { $rand = rand() % strlen($charset); $tmp = substr($charset , $rand , 1);

}

$query = mysql_query("SELECT code FROM files WHERE $code='$code'");

$numrows = mysql_num_rows ($query);

}

if(move_uploaded_file($tmpname[$i], "upload/$code/".$name[$i])) {

mkdir("upload/$code");

echo $name [$i]."Download File";

}else{

echo "Error upload".$name;

}

}

}

?>