помогите найти ошибку<?
//тут системные файлы
$LMI_HASH = isset($_POST[\'LMI_HASH\']) ? strval($_POST[\'LMI_HASH\']) : \'\';
$LMI_PAYEE_PURSE = isset($_POST[\'LMI_PAYEE_PURSE\']) ? strval($_POST[\'LMI_PAYEE_PURSE\']) : \'\';
$sum = isset($_POST[\'FIELD_1\']) ? strval($_POST[\'FIELD_1\']) : \'\';
$id = isset($_POST[\'LMI_PAYMENT_NO\']) ? strval($_POST[\'LMI_PAYMENT_NO\']) : \'\';
$LMI_MODE = isset($_POST[\'LMI_MODE\']) ? strval($_POST[\'LMI_MODE\']) : \'\';
$LMI_SYS_INVS_NO = isset($_POST[\'LMI_SYS_INVS_NO\']) ? strval($_POST[\'LMI_SYS_INVS_NO\']) : \'\';
$LMI_SYS_TRANS_NO = isset($_POST[\'LMI_SYS_TRANS_NO\']) ? strval($_POST[\'LMI_SYS_TRANS_NO\']) : \'\';
$LMI_SYS_TRANS_DATE = isset($_POST[\'LMI_SYS_TRANS_DATE\']) ? strval($_POST[\'LMI_SYS_TRANS_DATE\']) : \'\';
$SECRET_KEY = \'CX120389cX0X\';
$LMI_PAYER_PURSE = isset($_POST[\'LMI_PAYER_PURSE\']) ? strval($_POST[\'LMI_PAYER_PURSE\']) : \'\';
$LMI_PAYER_WM = isset($_POST[\'LMI_PAYER_WM\']) ? strval($_POST[\'LMI_PAYER_WM\']) : \'\';
$ID_USER = isset($_POST[\'ID_USER\']) ? strval($_POST[\'ID_USER\']) : \'\';
$code = md5($LMI_PAYEE_PURSE.$LMI_PAYMENT_AMOUNT.$LMI_PAYMENT_NO.$LMI_MODE.$LMI_SYS_INVS_NO.$LMI_SYS_TRANS_NO.$LMI_SYS_TRANS_DATE.$SECRET_KEY.$LMI_PAYER_PURSE.$LMI_PAYER_WM);
if ($code != strtolower($LMI_HASH)) {header(\"Location: index.php\"
;}
if($ID_USER == \"\"
{header(\"Location: index.php\"
;}
echo $sum;
//ут запрос на пополнение
echo\'Баланс пополнен на \'.$sum.\' WMR\';
exit();
?>