My developer set the PayPal module for the temporary URL. Now I need to change it to the permanant URL. However, the module shows that it is UNEDITABLE, see below

"NOTE: On www.paypal.com,
set your PayPal IPN Return URL to:
DO NOT EDIT.
This is the URL that PayPal needs to be configured to return to.

http://www.vintage-movie-poster.com/1folder/index.php?main_page=checkout_process"

What file does this URL above reference so I can confirm correct location?