Not sure why, but I had that problem for awhile with the Acali in the Mesoamerica scenario (with Windows XP). I'm pretty sure there's no historical information about them in the Civilopedia, though, and they don't have any special abilities (except you lose the game if they die), so as long as everything else is working you might as well just avoid clicking on them.
And if you want historical information, Wikipedia is a good place to start, and the local library probably has more information as well.