Supporter plugin doesn't seem to work at all?

I know this must be something simple, but my plugin is not working. On signup, it does not prompt them to become supporters even though I have set it to do so in the settings:

http://walamy.com/register

Also, I have banner ads using the code someone else posted earlier that is supposed to show the ads for nonsupporters, turn them off if they are a supporter. This isn't working either - it thinks everyone is a supporter.

http://walamy.com/members/admin/ (See at the top where it says "Is Supporter")
http://walamy.com/members/katy/ (non-admin still shows as 'supporter')

Can anyone shed some light on what I may have done wrong in installation? I followed the documentation to a "T" and selected "sandbox" for Paypal.