With the latest update, I have added code to detect commerce inconsistency. Usually, the overall player commerce and the sum of total commerce of all cities is supposed to be equal. However, in some reported savegames this was not the case, which can lead to crashes. I haven't been able to find the cause of this myself, and it was already too late in the submitted saves. So we are going with this. If the bug is detected during your games, you should receive an interface message along the lines of: "Detected a bug, please report latest autosave in the Dawn of Civilization forums". In that case, please report the autosave in the bug reports thread. I also encourage everyone to set their autosaves to every turn to make this as easy as possible. I have no idea how common or rare this bug is and if you will see this message at all. However I assume it is more likely to occur in the lategame.