customize fails

Hi,

when I want to customize an instance of kupu editor, I should click on 
customize button ("Select a destination folder and press the button to 
make a copy of this method that can be customized.")

However, clicking this button displays the following error message:

Error Type: AttributeError
Error Value: portal_skins

This looks like kupu tries to use Plone. Is Plone a requirement to 
customize KUPU ? I have plain Zope.

--
Milos Prudek