Question about chatroom client support

[Katrina Cooper]

My father and aunt would like to be able to three-way chat with me. I 
set up a chatroom for this purpose. Both my father and my aunt are AOL 
users, thus they have e-mails that end @aol.com. We "talk" one on one 
using Pidgin daily. I invited my father to enter the new chatroom and it 
worked perfectly. I invited my aunt, and got the message "not supported 
by client". This continued to happen. So... why would one aol address be 
OK and another not? What can I do about this?
Thank you!