If you are using GDK 7.4, there is another update that you need to download for the 3d renderer to work correctly. The download in the top post is the base library, but it has broken renderers, the download for those is about half a dozen posts below the top one, posted by Mike. It only contains the 2 files for the renderer that you need.
I had thought that the updates would have been consolidated into a single download by now, I can understand how easy it would be to miss the fact that you need the extra download if you dont read the entire thread(and who really does that ? I just skim through myself lol)
If it ain't broke.... DONT FIX IT !!!