This is probally some true and false. Several very serious security problems with AIM were fixed with release 4.3.2229. If you have an earlier version visit AOL and download the latest version.
In some chat rooms you can type in Whois Name and then it'll show you on screen that person's IP address.
This would get him to your server, then on the server someone could get your user /password/ etc, but he couldn't get to your machine----IF Your firewall is working. If its not and you had 'sharing enabled' your files are vulnerable.
Everyone should use firewalls.