What could be causing this crash in Alexander?

I am testing a mini-mod for RTW: Alexander, in which the Indians are a playable faction. The AI-controlled Macedonian faction, led by Alexander, starts with several large armies in Western Asia Minor. At the moment my efforts to make them launch an assault on Persia are in vain, as they just take Halicarnassus and then sit on their backsides for the rest of the game.

However, there is a serious crash which is perplexing me. If, while playing as the Indians, one pans the camera over towards the Macedonians after about turn 10, the game CTDs. I've narrowed it down to western Asia Minor. It's almost as if there's something there that the game needs to render but can't. It happens regardless of whether or not the Fog of War is on.

I haven't fiddled with anything except troop placement and garrisons, so the map is just the same as in the original game. I've tried deleting map.rwm in case it was corrupt, but the problem re-occurs.

Does anyone have any suggestions as to what might cause the game to CTD when trying to show part of the map?

Thanks :embarassed: