If you are sure that you are using FedEx you should be able to use these session variables to see the full request and full response:
full request: <?php echo $_SESSION["testCart_FedEx_FullRequest"]; ?><br/><br/>
full response: <?php echo $_SESSION["testCart_FedEx_FullResponse"]; ?>
This should get the full FedEx request and response. If you are using a different shipping provider this will not work though. If you still cannot get the full request and response to show please post back with a copy of the shipping failure page.
Based on my test of your site the error is saying 'no packages to ship'. How do you have the packages setup in this server behavior?