Comment 11 for bug 158756

Followup: I used to have a Debian global apt-get installation of setuptools in site-packages.
In addition, another global installation of setuptools as an egg, nto /usr/local/lib/site-packages, with a fresh version.

The latter one normally would override the previous one. This was the situation when the error happened at first.

After removing the Debian installation and repeating the buildout (bootstrap included) the problem goes away,
even though I _do_ have a globally installed Zope. That's very good.

So the problem is as Andi says concerned about setuptools (or maybe a lack of bootstrap on my side, but I don't think so. I can confirm later if needed.)