I'm not 100% sure what might be causing it. I've created an event to make sure I don't get the same problem, and I don't. I did however notice that if you are in Management Mode, that the paypal button will not work properly and just refreshes the page. My reccomendation would be to check the email address one more time to make sure there are no typos as well as checking paypal to make sure you are using the correct one, and then once you confirm that, make sure that you have fully exited out of management mode on your site by clicking on the red circle with and X in it. If that does not fix your troubles, then you'll probably need to send in a support ticket to see what might be going on.
