Ok,
In the Applications folder highlight iChat and then do a Get Info (Apple/CMD ( or ⌘) and i keys together).
In the panel that shows what version number does iChat say it has ?
Also in the Applications/Utilities folder can you open the Console app.
In the log/menu list down the side can you use the reveal triangles on ~/Library/Logs and find the Crash Reporter and see the latest log for iChat.
Can you copy that here ? (in this case include the Binary Images part)
Just to check - You reinstalled iChat this way ? (Easy way)
8:31 PM Sunday; February 12, 2012
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
iMac 2.5Ghz 5i 2011 (Lion 10.7.3)
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