PayPal IPN脚本不适用于捐赠者快递

Question

我试图使用DonatorExpress IPN脚本，但它总是给我错误500 ...

include('ipnlistener.php');        
if ($verified) {
    $errmsg = '';
        if ($_POST['payment_status'] != 'Completed') {
            exit(0);
        }
        if ($_POST['receiver_email'] != $paypal) {
            $errmsg .= "'receiver_email' does not match: ";
            $errmsg .= $_POST['receiver_email']."\n";
        }
        if ($_POST['mc_currency'] != $currency_code) {
            $errmsg .= "'mc_currency' does not match: ";
            $errmsg .= $_POST['mc_currency']."\n";
        }
        if (empty($errmsg)) {
        $useremail = $_POST['item_number'];
        error_log($useremail);
        $gross = $_POST['mc_gross'];
        error_log($gross);
        $newtoken = $_POST['custom'];
        $firstname = $_POST['first_name'];
        $lastname = $_POST['last_name'];
        $payeremail = $_POST['payer_email'];

我的ipn脚本： http://pastebin.com/4kx7ZgpM http://pastebin.com/zqFF1SfV IIS日志：

2015-03-10 16:07:02 148.***.***.14 POST /donate/ipn.php - 80 - 173.0.81.1 PayPal+IPN+(+https://www.paypal.com/ipn+) - 303 0 0 161
2015-03-10 16:07:02 148.***.***.14 GET /donate/ipn.php - 443 - 173.0.81.1 PayPal+IPN+(+https://www.paypal.com/ipn+) - 500 0 0 201