Crashing when selecting production!

[Unconquered]

I am playing in the modern era, and if I let the computer pick the production or if I choose production through the pull down it's ok. As soon as I enter the city screen and change production (only in certain newer cities) the game crashes and no message is given, it just dumps me to the desktop. It's anoying but I can work around it. Was wondering if anyone else was having crash problems. [WinXP, 1.5Ghz, 512MB RAM] Also, this only happens in the modern era.

[GeneralTacticus]

Were the units you (or the governor) were trying to build hidden nationality? I've experienced crashes before when trying to build hidden nationality ground units.

[simwiz2]

Were you using any modpacks? Because if you add a unit or change a unit's name but don't specify graphics files for it in the art/units directory then the game will crash when the unit is built or selected inside the city. The drop down menu would not crash it because it uses the icon.