magento worldpay doesn't redirect

I've upgraded from magento 1.4.1.1 to magento 1.5.1.1 and I have the Phoenix Worldpay extension installed. When in the checkout, the cart no longer redirects to worldpay after step 5.

If I go to /worldpay/processing/redirect, I get the error: No order for processing found

This is开发者_运维百科 thrown from:

    $session = $this->_getCheckout();

    $order = Mage::getModel('sales/order');
    $order->loadByIncrementId($session->getLastRealOrderId());
    if (!$order->getId()) {
        Mage::throwException('No order for processing found');
    }

Any ideas why?

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this error is thrown cause no order is loaded, check if the session has the data this extension needs

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I found the solution, it's not the plugin, it's in fact a problem with the checkout.xml layout file. I replaced it with a brand new version and it worked fine