I placed it in the UI folder then I got all of this "missing..... " texts written in the editor.You don't have to. You just create a folder named UI inside your warcraft 3 folder and put these three files there - TriggerData.txt, TriggerStrings.txt, and WorldeditStrings.txt. Make sure your copy of these files have no alteration. You can download these 3 files Here attached at the bottom of fthe tutorial.