Not working

Have you installed the Physical Fields module (http://drupal.org/project/physical) and the Commerce Physical module (https://www.drupal.org/project/commerce_physical)? You'll also need to add either a Physical Weight or a Physical Dimensions field to each Product type. These will allow you to enter the dimensions that can then be used by this module.

Be aware that the shipping calculator may still return this message if you add a product to your cart that doesn't have any physical field values assigned, or if the products of your cart exceeds the parameters of the Australia Post API. Best to test this out with a few scenarios to find out if/when the message is triggered and then change the message accordingly. For example, you might have a message that says "Your cart contains one or more bulk products so we can't calculate a shipping cost. Please contact us to arrange a special delivery"