I have some problem with my ldap server , can you help me
I have install:

openldap 2.0.27
openldap-servers2.0.27
openldap-devel2.0.27

I have run slapd
when I do :

ldapsearch -x -b '' -s base '(objectclass=*)' namingContexts

I have :
------------------result--------------------------------------
version: 2

#
# filter: (objectclass=*)
# requesting: namingContexts
#

#
dn:
namingContexts: o=organ,c=fr

# search result
search: 2
result: 0 Success

# numResponses: 2
# numEntries: 1
-----------------------end-----------------------------------------------------
---------------slapd.conf-------------------------------------------

# $OpenLDAP: pkg/ldap/servers/slapd/slapd.conf,v 1.8.8.7 2001/09/27 #20:00:31kurtExp $
#
# See slapd.conf(5) for details on configuration options.
# This file should NOT be world readable.
#
include /etc/openldap/schema/core.schema
include /etc/openldap/schema/cosine.schema
include /etc/openldap/schema/inetorgperson.schema
include /etc/openldap/schema/nis.schema
include /etc/openldap/schema/redhat/rfc822-MailMember.schema
include /etc/openldap/schema/redhat/autofs.schema
include /etc/openldap/schema/redhat/kerberosobject.schema

###### ldbm database definitions####################################
database ldbm
suffix "o=organ, c=fr"
rootdn "cn=Manager, o=organ, c=fr"
rootpw secret
directory /usr/local/var/openldap-ldbm

---------------------------------end---------------------------------------------
But when I add entry
example

-----------------test.ldif-------------------------------------------------
dn: o=organ, c=fr
objectclass: top
objectclass: organization

dn: ou=People, o=organ, c=fr
ou: People
objectclass: top
objectclass: organizationalUnit

dn: ou=Group, o=organ, c=fr
ou: Group
objectclass: top
objectclass: organizationalUnit

----------------------------End---------------------------------------------------
with

ldapadd -vxc -W -D "cn=Manager,o=organ,c=fr" -f test.ldif

I have the error

ldap_initialize( )
Enter LDAP Password:
add object class:
top
organization
adding new entry "o=organ, c=fr"
ldap_add: Operations error

ldif_record() = 1
add ou:
People
add objectclass:
top
organizationalUnit
adding new entry "ou=People, o=organ, c=fr"
ldap_add: Operations error

ldif_record() = 1
add ou:
Group
add objectclass:
top
organizationalUnit
adding new entry "ou=Group, o=organ, c=fr"
ldap_add: Operations error

ldif_record() = 1
-----------------------------------End----------------------------------------

I don't understand
can you help me please