[Plugin] Boolean--OSCoolean (Dec 2013) for SU 8 up free ver

[Dave R]

@nearlyman said:

I installed from download file: access to ‘extension warehouse’ failed due to a message statement “there is a script error on this page”...

I am installing on the 2013 version of Sketchup Make.

The Extension Warehouse hasn't supported SketchUp 2013 for a number of years.

As TIG wrote in the post immediately before yours, this extension hasn't been supported. There are other options available, though.