I'm running version 2.2 rc2 with Paypal Standard Payment module. I"m experiencing very similar problem. It was all fine for months. Today I received payment notification from Paypal but no receipt from Oscommerce and wasnt able to locate the order in the admin panel either. I have customer information so I was able to question him. I'm so embarrassed to have this difficulty on a live server. Please advise me how to avoid this in the future. I tested it myself and everything seems to be fine. I cant ask my customers what did the do, that I didnt get the invoice :( At this point I'm about to uninstall Oscommerce and switch to Zen.... .