This may be helpful to someone ! - I've installed this on an XP32 install on X79 motherboard with RME AIO - I do have MOTU interfaces such as 828 ES & LP32 & 2 X 896 MK3 (firewire).
OK - In the manual - a yellow A4 paper sheet for Windows it explains the directory path and where to put the library.
startup disk:\Program Files\MOTU\Electric Keys\Plug-in\Sounds\ -
- 
Suffice to say this did not work and I couldn't understand why but I did know the library should be recognised automatically.
After trying out a few things I put the library into:
C:\Program Files\MOTU\Electric Keys\Sounds\ - & Then it worked with copies of the links to the libraries
the folder "plugin" was omitted
