Nope, my bet is it's neither missing nor a bad install, you're just looking in the wrong "Library" folder.
According to the instructions you should be looking in the (public) Library folder found at the root of the hard disc ... my bet is you are looking in the (private) Library folder found at the root level of your User folder - but not to worry, you can install it in that Library too, just at a different path - ~/Library/Preferences/Final Cut Pro User Data/Plugins
I installed FCP recently. The problem is i can't locate the FCP data folder. I do have a library folder but its not in the users folder, its outside of it. Also no FCP folder available in Preference section.. If you could please explain.