Not sure I'm posting in the right forum so apologies if not. I'm trying to make a modified version by editing the text files. I've altered things like tech tree, unit capabilities, terrain stats, etc. Usually when I make an error in the text file, the program crashes with a "failed to start" message on startup and I can find out by trial-and-error which line is crashing it. But I'm also getting crashes with a different message - "Civ2.exe has stopped working" which happen either immediately after game setup or a few turns into the game. From switching files around I've confirmed it must be the Rules file causing the problem, but other than this I've no idea. Does anyone know what causes this kind of error, or how I could find out? I'm on Windows 7, x64, and running "Civilisation 2 Gold Edition". The only other time I've had the same error in a standard game is when I built airports in the maximum number of cities and then tried to airlift something.