[Zope] Security question

Hello, I have defined a new role. Zope is refusing me to add an object (of my own Python class), even if I check on all the permission settings for that role in the Security tab of the container folder (in a first step I turned only on some obvious permissions that role should have, but as Zope refused access to that role, I decided to try with setting on all the permission settings: it does not work better). Can someone help me and give some hints of why Zope is requiring that role to give password even when all permissions are checked on for that role ? Thanks in advance, Philippe Bocquillon