Unknown error adding AIM account

I have a client in France. She launched Messages for the first time and used her Apple ID to get it rolling. It works, but we are trying to add an AIM account to her Messages app so that I can use the share her computer feature.

We have a verified AIM account. When we try adding the AOL account we get "An unknown error occurred". Her Apple ID and her AIM username are the same email address.

Any thoughts on resolving the issue?

I tried to add the AIM account to my Messages and got the same error. Is there something we need to do in AIM to allow the connection? In Messages?