I see, in Universal Email if you choose to 'create a file for your email' with the checkbox you will have a page that automatically lists all of the fields and their values. I think it is a better way to go to use the bindings and add in the values where you would like them to be though.
On the Universal Email support page there is a link on the right side for archived documentation. In here you can take a look at the getting started guide for UE3 or the 'create an html email' section. I would have directed you to these resources earlier but I did not realize it was the message body that was coming up blank. Based on your first post I thought it was the page with UE on it that was coming up blank after submitting the form.