PayPal purchase to database link broken!

Looking for a PayPal / PHP expert to fix a broken link somewhere in an existing circuit. From this page - [login to view URL] - users can purchase a password or a password+CD or renew an existing password. Sometime yesterday, this system broke and I have no idea how to fix it. The programmer who set it up cannot be reached. The buyers receive a password for one year. They get this by email. Now I am getting warnings from PayPal that read like this: "Please check your server that handles PayPal Instant Payment Notifications (IPN). IPNs sent to the following URL(s) are failing: [login to view URL] If you do not recognize this URL, you may be using a service provider that is using IPN on your behalf. Please contact your service provider with the above information. If this problem continues, IPNs may be disabled for your account." When a purchase does go through it goes bananas, creating multiple accounts for a single user. Maybe we need to rebuild it? Attached is a screenshot of the database and what it looks like when multiple accounts are made.