[Zope-CMF] Nested CMF site access rights

[Cravoisier Thierry]

Hi all,

Zope 2.5
CMF 1.2
I also use LDAP authentification CMFLDAP.

I try to prototype a complete CMF site to manage project with public
area and specific secured projects areas.
CMF-1 Public
  CMF-2 Private (Projects site) 
    CMF-3 Project site 1
    CMF-4 Project site 2
People need to be authenticated to access content on CMF-2 Private
otherwise as guest they cannot see the projects site.
To do this I created a new role "Reader" on CMF-2 and changed access
rule for "Access Content Information": rights are not acquired anymore
and all roles except anonymous have authorization.
The role of Reader is just for authorized people to see (read) all
projects but not particularly to act on them.
Up to now everything works fine. I log on when required (CMF-1) and can
see all needed information (CMF2-3-4) in browse in them.
When I decide to log out at any other level than the level I logged in I
get the following error:
"Unauthorized: You are not allowed to acess protal_url in this context"

Since the access to content information has been disabled for anonymous
(right acquired from upper site) I connot find any relevant URL to jump.
This sounds normal, but would prefer to find back the latest authorized
URL.

What did I wrong ? Is there any smarter way to do this ?
Any feedback is welcome.

Note that I am just a newbee and does not know anything about python
programming. I currently try to figure out how to master all products. 

Regards
Thierry