Spike,
The "Sign In" button that's shown on your login page is not from JFBConnect. I'm not sure what extension is adding that, but that's the problem. You'll need to remove that button. You can always replace it with JFBConnect's Login button if you modify the template file for that login area and add {JFBCLogin}.
Hope that helps, but if you need more help, just let us know.
Thanks,
Alex