Somehow Windows 8 doesn’t bother to tll you why it fails. The emulation drivers are unsigned and on contrary to older Windows versions 8 is not asking the user whether he/she really wants to install unsigned drivers or not.
WinCDEmu installed perfectly fine for me on Win 8.1 Pro x64 by
1. following this
http://www.howtogeek.com/167723/how-to-disable-driver-signature-verification-on-64-bit-windows-8.1-so-that-you-can-install-unsigned-drivers/
2. running the setup as admin (shift+right click -> run as admin)
Hope this helps anyone