This is all on Windows 10 Home.
So I basically grabbed the ffmpeg-20150813-git-1bbb5ea-win64-static.7z from the Official Site for Win64 and then Extracted it to the following folder:
C:\Users\Raven\Desktop\Programme\codec then I opened ff-prompt.bat (C:\Users\Raven\Desktop\Programme\codec\ffmpeg-20150813-git-1bbb5ea-win64-static). After that I tried to open CrushedPixel'S ffmpeg-path-installer.bat but it always said the .exe is not existing.
But when I dropped the .bat Script in the same directory as the ff-prompt.bat it just said nothing. It gave NO output. And yes, the .exe exists.
The path of the .exe is: C:\Users\Raven\Desktop\Programme\codec\ffmpeg-20150813-git-1bbb5ea-win64-static\bin\ffmpeg.exe