error บรรทัดที่ 50 น่ะครับ แต่ดูแล้วโค๊ดไม่น่าผิดน่ะ แก้ตรงไหนดีครับ

<?php
include "masspay_class.php";

$credentials['API_USERNAME']  = 'username';
$credentials['API_PASSWORD']  = 'password';
$credentials['API_SIGNATURE'] = 'signature';
$credentials['API_ENDPOINT']  = 'https://api-3t.live.paypal.com/nvp';

$sitename = "PHPorium";
$amount   = urlencode($_POST['Amount']);
$id       = urlencode(rand(123456,123456789));
$note     = urlencode('This is a note that will show up in the email.');
$subject  = urlencode("Payment from $sitename");
$type     = urlencode('EmailAddress');
$currency = urlencode($_POST['Currency']);
foreach($_POST['mem_email'] as $extra)
{
    $customer_email = urlencode($_POST['EmailAddress'.$extra]);
}

$base_call = "&L_EMAIL0=".$customer_email.
              "&L_AMT0=".$amount.
              "&L_UNIQUEID0=".$id.
              "&L_NOTE0=".$refund_note.
              "&EMAILSUBJECT=".$subject.
              "&RECEIVERTYPE=".$type.
              "&CURRENCYCODE=".$currency;

$PayPal = new PayPal_CallerService($credentials);

$status  = $PayPal->callPayPal("MassPay", $base_call);
//Do something if it is successfully sent
if($status)
{
    if($status['ACK'] == "Success")
    {
        //Check the balance of the account that was just debited, and make sure we have at least $500 left in our account
        $balance = $PayPal->callPayPal("GetBalance", '');

        if($balance['L_AMT0'] < 500)
        {
            $message = "The balance is low... Please replenish the funds... \n\n".$balance['L_AMT0']." ".$balance['L_CURRENCYCODE0'];
            mail('[email protected]','PayPal Refund Balance Low',$message);
        }
    }
    elseif($status['ACK'] == "Failure")
    {
        if($status['L_ERRORCODE0'] == '10321')
        {
            $error = "Insufficient Funds to Send Refund to: "'.$_POST['EmailAddress'].' via PayPal in the amount of: '.$_POST['Amount'].' '.$_POST['Currency'].'. ';
        } 
        elseif($status['L_ERRORCODE0'] == '10004')
        {
            $this->view->error = "Invalid Amount of Refund to: "'.$_POST['EmailAddress'].' via PayPal in the amount of: '.$_POST['Amount'].' '.$_POST['Currency'].'. Must be more than 0 '.$_POST['Currency'].'.';
        }
        else
        {
            $this->view->error = "There was an unknown error when attempting to submit the payment.";
            var_dump($status);
        }
    }
}
else
{
    ?>
    <form action="paythem.php" method="post">
    <p>Amount To Pay:&nbsp;<input type="text" name="amount<?php echo $i; ?>" value="" /></p>
    <p>Select Members To Pay: <select name="EmailAddress<?php echo $i; ?>">
    <?php
    $i=0;
    $s=mysql_query("SELECT email FROM members WHERE email != NULL") or die(mysql_error());
    if(mysql_num_rows($s) > 0)
    {
        while($mail=mysql_fetch_array($s))
        {
            $i++;
            print "<option value='".$mail['email'.$i]."'>".$mail['email']."</option>";
        }
    }
    else
    {
        print "<option value='0' selected>no emails</option>";
    }
    ?>
    </select></p>
    <p>Currency:&nbsp;<input type="text" name="currency<?php echo $i; ?>" value="USD" /></p>
    <p><input type="submit" name="submit" value="Pay Now" /></p>
    </form>
<?php
}
?>