I was playing with a custom sovereign, and a custom made faction.
I clicked the end turn button, and it crashed.
Here are the debug.err, memory dump, and dxdiag:
Debug.err - http://pastebin.com/bGkRttYV
Memory Dump - http://dl.dropbox.com/u/5133286/Elemental0_295-2010-03-05T16-25-24-828.dmp
Dxdiag - http://pastebin.com/jD532DRF
I hope this helps.