[Zope] DocBook Samples: no security assertions error

Hi, As i try to view the sampleChapter of the SampleDocbookDocs, i've been asked to give my password! I gave my password, but it didn't work. I clicked of cancel and i saw following error: "Access denied for /users/in/SampleDocbookDocs/sampleChapter/e1986/CharacterData/getData because its container, /users/in/SampleDocbookDocs/sampleChapter/e1986/CharacterData, has no security assertions." Can someone help me. I don't found information about this problem and i'm new with zope and python. Thanks in advance. Cheers, Isabelle