There's nothing wrong with your screenshot; an icns file is just an icon image file. The top left corner of the "get info" window always shows the default file icon for the file type, not the custom-generated preview icon. Looks the same with every icns file on my system, as well as PDFs or anything else with previews in Finder. Quicklooking the file should show it, and it can also be opened in Preview to see all of the different sizes available.
Are you actually having a problem with this file? If so, what's not working?