Hi,
You both need to using AIM valid name or both using Jabber based IDs like FaceBook or GoogleTalk (oor Yahoo if you must)
Apple's @mac.com and @me.com are Valid AIM names as well as regular AIM names.
Jabber IDs are gained from non centralised servers and there are thousands of Public and private servers issuing IDs
Google Mail with "Talk" enabled on your Accounts settings or a FaceBook account with "Chat" enabled are valid Jabber IDs
Jabber IDs are rarely emails (Google is an exception).
However they follow the email format which means the AIM Buddy list will "accept" them format wise
(the same is true to some extent the other way round)
9:54 PM Monday; August 13, 2012
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
iMac 2.5Ghz 5i 2011 (Lion 10.7.2)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
"Limit the Logs to the Bits above Binary Images." No, Seriously