Question on "structural object classes"

[Harry Rüter <harry_rueter@gmx.de>]

Hi,

i'm having problems with importing a ldif file.
The content of the ldif-file is :

--------------------------------------------------------
dn: uid=admin, ou=ldap, o=myorganization, dc=hrnet,dc=de
krb5PrincipalName: ldapAdmin@HRNET.DE
gidNumber: 20000
userPassword:: aG9lbHpp
uid: admin
uidNumber: 20000
objectClass: krb5Principal
objectClass: posixAccount
homeDirectory: /etc/openldap
cn: ldapAdmin
---------------------------------------------------------

Importing this file gives errormesage :

------------------------------------
03:56:46 PM: Failed to add new entry 
uid=admin, ou=ldap, o=myorganization, dc=hrnet,dc=de
Root error: [LDAP: error code 65 - no structural object
classes provided]
------------------------------------

Which "structural object class" should i provide.
I'm a little confused, as in 
version 2.2.2x the above entry worked (and works)
fine.

Any hints from the community ?

Greets Harry