Back in 2010 when LightUp was first launched, SketchUp had no support to install Plugins and Extensions. This meant LightUp had to have its own installer to copy files to the correct locations.
Starting with SketchUp 2015, there is now a built-in Extensions Installer that offers a simple method to install plugins via .rbz files. It lives in Preferences->Extensions->Install Extension
We have started to transition over to using the SketchUp Extensions Installer system for LightUp. Initially it will be for the free 30-day DEMO on WIndows.
Please let us know if you have questions are problems.