Login troubles with afs 3.4 and aix 4.1

[RENATA]

We have brought afs 3.4a up on an aix machine running 4.1.4.  We have
users who have Unix accounts who are unable to login.  If the user  
has both an afs and a (different) Unix password, the afs password  
allows him to login but the other Unix password is not authenticated.   
Does anyone know what needs to be done to allow people to login with  
a Unix password in this situation?