Private Folders with Mac Os X

I’m trying to setup a folder on a MBW 1tb that’s simply password protected, via mac os x.  The folder appears but whenever I click on the folder it says the ‘original item is missing’, and I can’t connect.  Is there something I’m doing wrong?  Or is creating a password protected folder unnachievable? 

Which my book world and what OSX are you runing?

My Book World 1tb and osx 10.6.7