[Edi]

Probably something has gone corrupt with that particular game. I've had that happen when the map had specified non-existent monsters in the province (monster ID greater than 1772) or non-existent sites (sites above 565) or there were too many #knownfeature commands in the mapfile. Right clicking in the province where the offending items were in view would get an immediate crash to desktop. This could be something similar but not quite the same.

Edi