I too had a problem getting the unit viewer to work, but my setup is different enough from those described above that I thought it might be worth a comment. I had version 1 of CSME, and when I upgraded to version 2.0 the installer directed me to uninstall version 1 first, which I did. Now on my Windows 10 (64) machine the installer wants to put CSME 2.0 in the Program Files (x86) subdirectory of the installation drive, but Control Panel's uninstall left intact some files from the older version of CSME. So, since I installed both versions of the game on my F: drive, I have these two directories: F:\Program Files (x86)\Matrix Games\Campaign Series Middle East (which contains the tools\CS_UnitViewer subdirectory with the settings file you need to change), and F:\Matrix Games\Campaign Series Middle East (which corresponds to the directory paths described above, but appears to contain left overs from uninstalling the earlier version of CSME).
Obvously, if I follow the instructions above exactly I'll be pointing the UnitViewer at the old (nearly empty) directory, and it doesn't work. The simplest way I found to create the path you need to make the utility work is to find the directory with the settings file, copy the full directory path and paste it in place of everything to the right of the = in the settings file, then backspace over the references to the tools and unit viewer subdirectories.
So then my settings.txt reference gets initially changed to: Middle East=F:\Program Files (x86)\Matrix Games\Campaign Series Middle East\tools\CS_UnitViewer
and from that to: Middle East=F:\Program Files (x86)\Matrix Games\Campaign Series Middle East.
I hope this helps.