pay_node - unabled to remove linked forms

If you have a content type setup with pay_node to allow linking to existing forms.. and you have a node (say a page) that is linked to a pay form using pay_node, and you try to remove the link by editing the page and selecting "-None-" in the drop-down list, it gives you a PHP error message about foreach and fails to remove the association.

I believe that the attached patch fixes the problem.