I have been using AOL Instant Messenger (for Mac, v 4.7) for months without incident. However, since last week, I have been unable to enter any AIM online chat rooms. I am logged onto the AIM client, but when I try to enter a chat room, I get a message back that the "Request has timed out" or, less frequently, "AIM is unable to do what you requested." I have the most current version of AIM for Mac, and have no trouble chatting with existing buddies on my Buddy List when they are online, but am unable to enter any AIM chat room. What could be causing this problem and how can it be fixed?