I'm nearly positive you just extract the folder and run Zerahypt.exe. There isn't even an install. That's what I did. Edit: Come to think of it, you don't even need to do that. You could just run Zerahypt.exe from the RAR file. Of course, then you would have to wait until Half Life 3 comes out for it to finish extracting the executables for temporary use.
Are you on windows? Also if you are on windows 7 then you don't need winrar to extract the zip file just right click on the zip file and click extract
The files don't actually exist when you just double-click on the zip, windows is just showing you a list. Don't double-click on the zip file, right click, extract here. Then go into the new folder.