Which operating system are you using?
It seems to work okay on windows 8.1 x64 in the 32 bit version of photoshop cs6 13.0.1.3, barring a few menu glitches in the plugin dialog.
I actually used the color efex pro 3 plugin installer and pointed it to
C:\Program Files (x86)\Adobe\Adobe Photoshop CS6\Plug-ins
