The purpose of the tool is not to extract and replace files.
The tool works independently - in it's own folder.
You got this message because you replaced the file ... You need the original data.package file for your locale .. Run my tool, select your locale of choice .. Done ..
You do NOT need to run this tool in any "SimCity" folder .. You can run it on your desktop - but I would recommend running it inside the folder that it is in when you extract it. Anyone claiming that it should run inside a SimCity folder or that you should replace locales is wrong .. If you do not own a SimCity with a selectable language equal to the one you wanted it will not run when you replace the files and get the message like you did.
Tool is not manual. It's supposed to be automatic.
ok thanks for the tip.
I will try it again.