#15 Error: cannot modify object class

[Udo Rader]

I've a debian based openldap 2.1 running, ldap v2
binding is allowed.

Using diradmin I see all users and groups, but I cannot
change anything (tough I can delete).

Changing for example the first and lastname of an user
results in this msg:

"Error: cannot modify object class"

Changing the access controls to "grant access to all
computers in the network" ends in:

"A required field is empty, has invalid characters, or
your directory does not support a required object
class. Please complete missing fields, ..."

Any ideas?