Email Address Field Not Working

I am developing a form to receive payments and would like to setup the automatic reply feature. However, when I check the email address form in “Form Settings” it does not show up on the form on my page or in the preview window. I have tried numerous times and no luck. If I check the “required field” for email address in “Form Settings” the form will then not allow submission because of the incomplete field, even though the field is not visible to be filled out.

The page I need help with: [log in to see the link]