The sound file is embedded in the CleanUp! executable program so it cannot get "lost" as such. So, if you don't hear the sound, more than likely it has something to do with the sound setup on your machine. Can you hear other sounds from other programs?
I have the same problem, no more sound in Cleanup, even with "Enable sounds" activated.
I don't have any other problem with any other souns on my system, only with Cleanup
Thanks for solution,