Help ichat

i have a second hand g4 i book and i cannot get i chat to work, it says international inconsistencies in the thread. i have not been able to open it, it says no ichat defaultAny help would be appreciated. thanks joan:

This sounds like someone used a "language scrubber" like Monolingual on the system and destroyed some files that iChat (and probably other programs) needs.

The only way I know to fix that is a system reinstall.