Yes, I have paypal.php file. But I followed the contribution http://www.oscommerce.com/community/contri...1/search,paypal, which replaces the file with paypal_ipn.php for the paypal IPN module.
I have the same problem. I am confused by pixclinic's reply. Isn't it includes/modules/payment/paypal_ipn.php file instead of includes/modules/payment/paypal.php? How can I modify the file includes/modules/payment/paypal_ipn.php?
Thanks,
--Ray