I don't understand the issue exactly. Do the default sounds currently work on your system, or is it just customizing them that doesn't work. Currently the sounds do work on my machine and I have latest version of MacOS I think.
Jasem, KDE packages can't be installed on MacOS the way they are on Linux. The dynamic libraries required for the sounds to work as well as the sounds themselves are in the app bundle in the DMG and should be copied to your system when you drag and drop the app bundle to your machine.