This explains your error. Basically SPIN/iGateway framework that hosts EEM and ECLI is getting confused. ECLI in the AE install always installs a 32bit version regardless of the OS, EEM requires a 64bit version on a 64bit OS, and so fails if a 32 bit version is already installed bug in the installer.
So remove all SPIN/igateway components, then from the COM dvd install EEM specifically go to the directory (do not use the default installer) and force a 64bit install. Check EEM is installed and working, then WCC, and finally the ECLI component (if you need it) again from the specific directory on the AE dvd (not using the default installer).
Good luck with the clean up and then re-install