Thanks for responding!
Maybe I'm trying to access it incorrectly. I go to browse local files under the properties option. I open the Galciv2 folder, then the Twilight subfolder, then the Tools subfolder. I run the Galciv2 map editor as administrator.
It opens up to a background with a huge patch of white and some small colored squares with a medium amount of black background. I can see the map grid as a blue outline, but that's it. It seems that I can place some objects, but I can't see what I am doing.