The Universal Email server behavior you have here looks like it has the trigger set to same page post and the recipient is set to $_SESSION["eCartCheckoutForm_email"]. If this value is not set there there is no email that will be sent.
Are you not able to edit the server behavior? The code that is on your live server should not have changed and should be functioning the same. Please let us know about the issues you are experiencing with the UE server behavior.