Form shows 'thank you' text before completion, and doesn't register people

form can be seen at: at the bottom of the right-hand sidebar.

The form shows the ‘Thank you, your email will be added to the mailing list once you click on the link in the confirmation email.’ text prior to the submit button being clicked, and when an email address *is* entered, it does not get added to the list of registered users (which currently only has one address, which was a manual addition).

please advise ASAP.