Yes, the email is one of my registered members that placed an ad. So why would it be saying "user unknown". Also, if it is my mail system, why does it send the emails in some cases but not the others. I don't get those bounced emails when those same users are receiving notifications of posts on the forum and etc. Only the classifieds.
And I certainly don't show as many members in the classifieds. I show 11,084 registered forum members. I also show that same number of registered users in the Photopost Admin area at the top under Registered users. But if I click on "member list" in the menu bar at the top of the classifieds, it only shows about 68 members.