@biz295654 - The action page is that page that will process the form. you have 2 options:
1) Leave the action page as is, the form will submit to itself. If you do this, you will need to edit the universal email behavior after the form is created to redirect to the thanks you page.
2) Set the action to go to the thank you page. This will apply the validation and universal email code to the thank you page, it will send the form data directly to the thank page, if validation fails, it will go back to the form page, if not it will send the email and stay on the thank you page.
if the email is blank, it mens you did not set up the email body. In the Universal Email behavior, either select the option to create a file for the email message, and select one of the templates (recommended), or click the DW Edit button to configure the email body.
@Ian H - One issue i see on your page is that there are 3 instances of the server validation behavior, there should be only one. delete the other 2.
You have set universal Email to redirect to the thank you page after sending the email, if the redirect is not happening, it means that either validation is failing, or there is an error on the page.
try adding the following code to line 1 to turn error reporting on:
when the page posts, do you "?invalid=true" in the address bar? if so, this means validation has failed and is the cause of the problem.