Well, I can create map big enough for my liking (for now , but can't create biggest ones.Sorry, but I'm uncertain about what you're saying. Are you able to create maps that are large enough for your liking, and it's just larger maps that don't work? Or are you still unable to create any maps at all? If it's the first then you probably can't create maps over a certain size due to the limits of your computer. If it's the second then I have no idea what the problem is.
About limits of my computer, I don't know. If it depends on video memory, it might be that civ developers did not expect 320MB cappacity. But ram(2GB) and CPU(c2d 6420) should be enough I believe. Also it might have something with OS on my desktop.
My laptop has much less resources, so lack of them is probably cause there.
So generally thanks for nice script
Feel free to remove my posts, as they are not much contributing.