I am having the same problem. I am running AIM on my Mac. I am using the latest version (4.7), but neither AIM or iChat will allow me to sign on with any of my screennames. I thought it might be a host server and port problem, but I can’t find any successful alternates. I have uninstalled and reinstalled – tried everything, but no luck. If any one has a list of servers and port numbers that work for connecting to AIM, that would be very helpful. OR if you know how to fix this problem a different way, let me know. Thanks a lot!