connecting to ldap with credentials to 10.5.2 openldap via ldap administrator tool

I use ldap administrator tool o connect to 10.5.2 ldap master. When i connect using anonymous user it works and all structure appears. i can backup, but not modify entries. So when i'm using simple or GSS Authentification using Principal: cn=diradmin and my password for user diradmin i get an invalid credentials, and diradmin and password are correct. What can i do ? Mike