FedEx Shipping Error in Magento 1.4.2

In magento, we are getting the error message below anytime a customer tries to checkout and use FedEx for shipping. I contacted FedEx to inquire why we are not getting shipping quotes from their server and they informed that Magento is not even pinging their server. So Magento does not even attempt to send shipping information to FedEx once the customer has entered their shipping address. We have installed the extension to allow Magento 1.4.2 to use the new FedEx API but as shown by the error message below, Magento is not acknolwedging the customer has entered in their address when in fact the customer has completely filled out their shipping information. This project requires that the FedEx shipping option be fixed in Magento 1.4.2. Error message: "This shipping method is not available, please specify ZIP-code"