http://help.sketchup.com/en/article/115754 and others have links to examples that all return 404 link broken. FYI.
Thanks @enuminous, you are correct.
Sorry about that. I updated one of the tabs to point the SketchUp example models to the new 3D Warehouse, but I failed to replicate the change across all the tabs. Feel free to try again in another 30 minutes or so.