php , Authorized.net pay

Question

I'm using Authorized.net Pay Pal and I have a error occur when the payment process

Exception: Invalid operation, the value type is invalid.

$ret = 
    gt_exec('purchase_card',
        $user_email,$user_pass1,
        array(
             'bill_to'       => $addr_bill->ToArray(),
            'ship_to'       => $addr_ship->ToArray(),
   'subtotal'      => $tot_price,
            'tax'           => $tot_tax,
            'shipcost'      => $tot_ship,
            'cc_number'     => $cc_number,
            'cc_expiration' => $cc_expire,
            'cc_cvc'        => $cc_cvc,
        ),
        $items,
        $arr_card);

i get all the values in the code