The command try to create the symbolic link, and here apparently the file//folder is not available … do you have something like that in your explorer ?
Why? There are still reasons to use FAT. Not every platform supports NTFS or journaling file systems. My digital mixer, several samplers and most of embedded platforms have no clue about NTFS, especially when it comes to changeable flash memory .
However I’m with you on PC platforms like Windows or Mac.
I had the same issue. Running the armory blender.exe as admin worked for me.
Perhaps admin privileges are needed to create the symbolic link when armory is installed in certain directories.