Okay.. trying to take the settlement back results in a CTD. I suspect it has something to do with the animation when the invisible family member dies. The ghost Seleucid in question is named Artaxias Sophenikos and he's 59 years old at this point, which is 251 BC.

Here is the save game, right before i try to retake the settlement causing the CTD.

http://uploaded.to/?id=ran4b1

Oh, and i'm running EB 1.1 with the BI .exe and I've installed all the 1.1 fixes that's come out.