Note that in v2017 this installer-button has moved into Window > Extension Manager, and is 'red'. The latest RBZ archive needs to be installed using Window > Preferences > Extensions > Install Extension. It's linked in the big pink block in this old thread's first post. Get the latest RBZ from the PluginStore - it's at v4.0: First off - remove the Roof RB file/subfolder from Tools.