HI Celmar . 
Q: What happens when you install the native content,. Q: what error messages do you get,.?
Any screen captures of what’s happening,.. or what you’re doing,. would help
It’‘s very strange if Windows 8 has any problems with the content being installed,. since it’s not an application, it’s just a bunch of scene files and texture maps. ..so there shouldn’t be any problems with the actual content files, but the product installer is a little application, so that could possibly have an issue,.. but,.. Win 8 should have “compatibility modes” for older software,.. to allow them to run.
Any info you can give about what you do, and what error messages, and why windows8 won’t allow you to install the content, may help.
I think most people are still on Windows 7,. ..so,.. there may not be a rush of people jumping in with a fast answer.
