Warning: Invalid argument supplied for foreach()

Hi,

I have an error with Marketpress when I add products to the cart. The error is:

Warning: Invalid argument supplied for foreach() in /homepages/39/d272077634/htdocs/wordpress/wp-content/plugins/marketpress/marketpress-includes/template-functions.php on line 1725

This can also be seen on your demo store: http://wp-ecommerce.org/store1/ and /store2

Do you have a fix for this?

Thanks

Adam