Did you also install the latest Lib Fredo needed by the tool as a helper, and the latest version of SketchUcation Toolset v4.2.6 needed to properly checking its licensing ?
These are both needed for it to run...
Restart SketchUp after the extensions are all install and retry...
If you have has the extension install previously, even if you have never used it, then its 'trial' date runs from the first installation, not its first use...