[Ashish Kumar (Ashfame)]

Instead of uploading to bb-templates folder, create a folder my-templates in the bbPress root and upload the theme to my-templates folder.

Then you can activate it under the Appearance options.

If you face issues, then fix out their permisison issue by following this tutorial : http://blog.ashfame.com/2009/09/fix-my-templates-my-plugins-folder-not-working-bbpress/