Hi,
On a Mac, the first account set up is usually the Admin account.
You can create more Mac Users Accounts in System Preferences > Accounts (Or Users and Groups in Lion).
These can be more Admin accounts or Standard accounts
With a Standard Account you can set up Parental Controls.
If this has been done for iChat you will not be able to Add Buddies ( or more iChat Acounts).
Either the Admin has to Add the Names to the Allowed List in the Parental Controls or Parental Controls need to be turned Off.
9:03 PM Friday; December 30, 2011
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