[Plugin: WordPress Ultra Simple Paypal Shopping Cart] Duplicate checkout button

ok i have the latest version of wordpress installed and the latest version of this plug in. however i am having some issues with the payment button using internet explorer.

On my checkout page i get 2 paypal buttons. i have tested using all browsers.
in chrome and firefox only 1 checkout button is displayed and redirects correctly to paypal.
however using ie 7, 8 or 9 you are presented with 2 paypal checkout buttons. 1 of them does nothing and the other takes you to a page about signing up for paypal.

please help as ie is used by the majority of people

http://wordpress.org/extend/plugins/wp-ultra-simple-paypal-shopping-cart/