I got Audaciity 64-bit, but the only link offered to download FFmpeg 2.2.2 is 32-bit.
I searched Google and can’t find FFmpeg 2.2.2 64-bit Shared.
Where did you get Audacity from?, I though it had 32-bit versions only.
The 64-bit version of Audacity for Windows hasn’t been officially released yet so you’re mostly on your own.
You may be able to use FFmpeg as an [u]external encoder[/u].
Currently we only provide 32-bit builds for Windows.
The official 32-bit release version can be run as a “portable” app quite easily: https://manual.audacityteam.org/man/portable_audacity.html