These are the debug messages that came through:

1. IPN PROCESSING INITIATED.
*** Originating IP: ########### (masked)
*** Browser/User Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;


2. IPN FATAL ERROR :: No POST data available -- Most likely initiated by
browser and not PayPal.

3. IPN FATAL ERROR :: Could not find stored session in DB, cannot re-create
session as PayPal IPN transaction.

4. IPN FATAL ERROR :: No saved IPN session data available. Must be an Express Checkout or Direct Pay transaction.

5. IPN INFO - POST VARS received (sorted):
Array
(
)

What do they mean? Did they make changes to the IPN handler that requires a static IP address?