Problem in registration about collective.etherpad HOT 1 OPEN

Then added all files form the git https://github.com/ether/etherpad-lite.git to a new plone installation.

I don't understand this ? Why are you doing this ? Have you read the provided buildout ?
But you said etherpad is installed so ... lets continue

In mysite/plone_control_panel I also have added the product.

OK, so the addon is installed.

The problem rise when I go in the ZMI to: /portal_registration

Why are you going to portal_registration ?
Why are you trying to add collective.etherpad.layer.Layer and where ? This is a browser layer and it is registred by the profile, so it's added to the 'request' by plone.browserlayer.

I really don't understand what you are trying to achieve. Please add more information.

from collective.etherpad.