Playing in my AS campaign, I've encountered a persistent CTD. It occurs in 229 BC - I have the Ptolemaic city of Hibis under siege, and once I press end turn the Ptolemaioi attack me on their turn with a supporting army. Three times now I've destroyed the relieving army and the city garrison in the ensuing battle, capturing the city; however, once the Ptolemaioi turn ends and I get the option of deciding the settlement's fate, the game crashes as soon as I choose to execute the population. Any ideas why this happens?