Cannot send data using form from index.php

I've run in to a small problem and I hope someone can help me out.

I made a form and it works fine:

http://www.volunteeringnews.com/formorg.php

If I hit send it returns a message saying User has been created.

So that works but if I go to http://www.volunteeringnews.com/ and under "Organisations" I click Submit it doens't work. And the Submit button is justa link to formorg.php.

I tried adding this to index.php but that was no success.

$action = isset($_POST['action']) ? $_POST['action'] : "";

//include database connection
include 'mysqli.php';

Can someone have a look?

Thanks!