You'll find that even opening up the ports as sugested won't fix the problem. AIM is backwards enough that it sends its IP address to the server in the data of the packet. Thus, you have to rewrite the packet to actually get it to work. It is rumored that the new version is better, but I havn't tried it out.

One thing that came up on the BBS recently is Reaim, avaible here: http://reaim.sourceforge.net/ but it's going to require a linux box on the outside, and some knowledge of what needs to be set up.

Matthew