Internal iChat Error Occurred when Starting

I don't know why I can't be able to start ichat. Every time I try to open it, an error will appear. I searched for some solutions online and already followed what they suggested such as removing the library prefs, reboot my modem and router and repair the disk permissions. However, nothing works so far. The error I've got is listed below:

An Internal iChat error occurred.
IChat couldn't connect to iChat Agent.
Quit
