I assume you are using the form builder with bravenet

so login and get the COMPLETE html code for your form and DO NOT erase anything in the code keep it as it is when it generates the code for you after you have made your form.

I can tell you right now missing very important coding for your form to work so do not EDIT ANY of the code for your form.

so as said login click webtools click on the bravenet form link and the form you have made then get html code for the form then put the code on your site using the code editor tab and save and publish your page again and try the form again

It looks as if you have taken a Bravenet email form and then carefully removed every possible bit if code that will actually make it work. Go back to the beginning and only change the bits that they say are user maintainable.