The CEP is composed by two files, both needed to have colour options.
the files are:
1) _EnableColorOptionsMMAT.package, located in [gamedir]\EA Games\The Sims2\TSData\Res\Sims3D
2) _EnableColorOprionsGMND.package, located in your Downloads folder.
Both files should be automatically installed in the proper locations when you double-click on the installer (ColorOptionsSetup.exe).
Please check the said folders and see if the CEP files are where they should.
If you can't find them, perform a complete search on all the hard disk(s) for files starting with "_Enable" (notice the leading underscore) and report me where they are located. They must be on your computer: the installer may have put them in the wrong folder, and you have to delete them before anything else, otherwise there may be conflicts between the multiple copies.

Another thing to check is if you have in the Control Panel / Add-Remove software an uninstall entry related to the CEP.

Your info will help me determine if the installer works properly, thanks.