this seams to be a bug when using a custom button image:
<input type="image" name="submit" src="http://www.bondstars.com/images/add_to_cart.gif" border="0" alt="Make payments with PayPal - it's fast, free and secure!">
I have logged this in our system to be corrected in a future update.
in the mean time, set the button to use a paypal image:
<input type="image" name="submit" src="https://www.paypal.com/en_US/i/btn/x-click-but5.gif" border="0" alt="Make payments with PayPal - it's fast, free and secure!" />
you can change it back after editing the button settings.