It is best practice to never modify the stock data files. Instead, create a mod folder (any name will do) and copy the data folder in there (including the folder). Make any modifications to this mod, not to the stock files. You can use Path.txt in the root SE4 directory to tell SE4 to load with that mod (just the name of the mod folder will suffice), or use the Mod Launcher, which can be found on the Gold CD (or a newer Version is available on
SpaceEmpires.net ).