When trying to dominate another civilization culturally, there seems to be a problem.

I was playing a custom Civ in my last game, the Terran Alliance was my neighbores. I built a seriesof influence bases throughout their star systems and by the summer of 2229 the Humans were so obsessed with my civilizations that a chain of rebellions throughout their empire brought most of their planets under my control. BY July, 2229, Mars was the last Terran controlled planet in the galaxy. Less than a month later rebellion breaks out and the exhuasted government of the Terran Alliance is no more.

Crash To Desktop....

What happened? Has anyone else had a CTD upon conquering an entire civ culturally?