Oscommerce Payment mod error

My oscommerce site is experiencing payment error, For some reason checkout is hanging after payment information is entered. I am using paypal and googlecheckout and the site wouldn't link there once payment information is entered. you could see that yourself at mysite [login to view URL] Please beware that the googlecheck mod has programed as default check out instead of alternate checkout, so while working on the problem, I wish to keep that as default check out. I wish to fix this error timely please contact me. Thanks