For a mistake the first time I ran and installed the cognos-setup.bat script inside CognosConfig package for connections 4.5, I installed both Transformer and BI Server on the same folder, E:\IBM\Cognos64.
I fixed the error into cognos-setup.properties ( Transformer into E:\IBM\Cognos and BI Server in E:\IBM\Cognos64)So I removed everything with uninstaller on E:\IBM\Cognos64\uninstall. Only the BI package was available for removal.
If I try to run again the cognos-setup.bat script, the tiny Cognos Stream Installer in the upper left corner was every time getting this exception
you cannot install this version of the product over a previously installed version
After checking and doublechecking (regedit show no presence of any transformer reference, and I also tried installing and removing Transformer with standalone installer on the wrong directory, to be sure everything is correctly removed from user registry or whatever).
At the end, I had an idea: the response file for perfoming installation was still held into the AppData/local/temp folder. I uninstalled everything with Cognos uninstaller, removed physically the folders where I was installing, and purged everyhing in here
(If you can't see this folder with explorer, just type it in the path)
Now run again cognos-setup.bat and everything will install correctly