[Zope] Authorization problem with python module

Hi Everyone, I have a security problem with a python script in Zope (2.7.0). I try to import a not very common python module to use some of is method in my script. In the _init_.py of the product that use this module, I have checked if "allow_module" and "allow_class" is correctly set ans all seems to be ok. The problem is when I use one of the method of a class of that module in my script, a message box appear asking for my login and password and if I write my user name and password (manager) it doesn't work. I receive message like: you have not the authorization to access this method in that context... Someone have an idea of what I'm doing wrong? Is there a way to bypass this security check? Thanks a lot Etienne