Problem adding sambaGroupMapping

Hi,

i show the command-output trying to add the objectClass sambaGroupMapping to some entries that have posixGroup objectClass:

root@amahoro:~# ldapmodify -x -W -D 'cn=Manager,dc=amahoro,dc=bi' Enter LDAP Password: dn: cn=Students,ou=Groups,dc=amahoro,dc=bi changetype: modify add: objectClass objectClass: posixGroup objectClass: sambaGroupMapping sambaSID: S-1-5-21-251852451-2940789264-3475694606 sambaGroupType: 5

ldapmodify: wrong attributeType at line 6, entry "cn=Students,ou=Groups,dc=amahoro,dc=bi"

I don't know what is wrong, sambaSID is a correct attribute. Do you have ideas?

Thanks