The form builder wizard should not be used for editing the email settings.
to edit the email body, you need to edit the email template file. see the following tutorial for details:
http://www.webassist.com/tutorials/Customize-form-elements-in-your-form-generated-emails
The form functions tab is really only relevant when Creating the for and should not be used on editing the form.
to edit the form functions, you would edit the server behaviors for either Universal Email or file upload by opening the server behaviors tab and double-clicking the corresponding server behavior.
