The problem is on your end, I have launched the cmd file from your archive and the maker successfully made the sfx:
Since I can't access your machine, I'm afraid I can't help further.
If the only thing you need is to add the key file, you can update the setup with this command (adapt the names) :
"%Programfiles%\WinRAR\Rar.exe" a winrar-x64-701fr.exe rarreg.key
Then use the switch /S to install it silently.
Spaces or special characters in the path where you have extracted the archive, I can see you have one in SFX MAKERS already.
Try to use it in the root folder of one of your drives.
Maybe your AV is blocking the file.
I've created a Bulgarian version and it installs fine, here it is: https://www.sendspace.com/file/n9t2eh
Can you share the sfx created ?