Impossible to install CIS 8.1.0.4426 on Windows 8.1x64, because Error 1603 stop installation? The problem with the file cmdstat.dll.
How I have found it?
Unzip installation file cispremium_installer_6100_08.exe with program 7-Zip and in folder cis-download-installs-xml_binaries-cis find file cis_setup_x64.msi. It is firewall and antivirus. Run and install program. In the and of installation you will see message - impossible to register file cmdstat.dll. This problem can be avoid if current language for non-Unicode programs is English. In my system the current language for non-Unicode programs was Russian. So I have changed language for non-Unicode programs on English, installed CIS and then changed again on Russian. CIS work perfect!
I was trying two days to install CIS in windows 8.1 64bit. After changing language for non-Unicode programs to English as oyu suggested, the installation finished successfully and CIS seems that it runs ok.
Thank you.