Magento: Créer un programme en arrière-plan code

J'essaie de créer une commande dans le backend de Magento (1.5.1.0).

Voici un code:

        //Get the product id stored in the optionValue of the widget
$productId = $order['customIdNumber'];
//Load the product
$product = Mage::getModel('catalog/product')->load($productId);
//Check whether the product could be loaded
if($product->getId())
{
//Get the customer model
$customer = Mage::getModel('customer/customer');
//Set the website id associated with the customer
$customer->setWebsiteId(Mage::app()->getWebsite()->getId());
//Try to load the customer by email
$customer->loadByEmail($order['personAddresses'][0]['email']);
//Check whether the customer not exists
if(!$customer->getId())
{
//Create the customer
$customer->setEmail($order['personAddresses'][0]['email']);
$customer->setFirstname($order['personAddresses'][0]['firstName']);
$customer->setLastname($order['personAddresses'][0]['lastName']);
$customer->save();
}
//Set the esstial order data
$orderData = array(
'currency' => $order['currencyCode'],
'account'  => array(
'group_id' => Mage_Customer_Model_Group::NOT_LOGGED_IN_ID,
'email'    => $order['personAddresses'][0]['email']
),
'billing_address' => 
'firstname'  => $order['personAddresses'][0]['firstName'],
'lastname'   => $order['personAddresses'][0]['lastName'],
'street'     => $order['personAddresses'][0]['street'],
'city'       => $order['personAddresses'][0]['city'],
'country_id' => $order['personAddresses'][0]['country'],
'region_id'  => 'BW',
'postcode'   => $order['personAddresses'][0]['postalCode'],
'telephone'  => '0123456789',
),
'comment' => array(
'customer_note' => "[Order has been created by the sellaround widget module]\nCustomer message:\n".
$order['personAddresses'][0]['message']
),
'send_confirmation' => false //does that something?
);
//Set the shipping address to the billing address
$orderData['shipping_address'] = $orderData['billing_address'];
//Set the payment method
$paymentMethod = 'checkmo';
//Set the shipping method
$shippingMethod = 'flatrate_flatrate';
//Get the backend quote session
$quoteSession = Mage::getSingleton('adminhtml/session_quote');
//Set the session store id
$quoteSession->setStoreId(Mage::app()->getStore('default')->getId());
//Set the session customer id
$quoteSession->setCustomerId($customer->getId());
//Get the backend order create model
$orderCreate = Mage::getSingleton('adminhtml/sales_order_create');
//Import the data
$orderCreate->importPostData($orderData);
//Calculate the shipping rates
$orderCreate->collectShippingRates();
//Set the shipping method
$orderCreate->setPaymentMethod($paymentMethod);
//Set the payment method to the payment instance
$orderCreate->getQuote()->getPayment()->addData(array('method' => $paymentMethod));
//Set the shipping method
$orderCreate->setShippingMethod($shippingMethod);
//Set the quote shipping address shipping method
$orderCreate->getQuote()->getShippingAddress()->setShippingMethod($shippingMethod);
//Add the product
$orderCreate->addProducts(array($product->getId() => array('qty' => 0)));
//Initialize data for price rules
$orderCreate->initRuleData();
//Save the quote
$orderCreate->saveQuote(); //neccessary?
//Create the order
$order = $orderCreate->createOrder();
}

J'ai toujours de l'exception "s'il vous Plaît spécifier une méthode d'expédition." dans Mage_Sales_Model_Service_Quote::_validate dans la lignée 293.

Code de l'lignes autour de l'exception:

    $method= $address->getShippingMethod();
$rate  = $address->getShippingRateByCode($method);
if (!$this->getQuote()->isVirtual() && (!$method || !$rate)) {
Mage::throwException($helper->__('Please specify a shipping method.'));
}

Quelqu'un sait pourquoi j'ai cette erreur? Est-ce parce que le taux n'a pas pu être chargé?
(Le produit n'est pas virtuel)