posixgroup & structuralobject errors

i am using openldap for many years now ( arround 300 users ) but recently i encountered some problems. i installed a new server ( opensuse 10.1) and tried to import an ldap database which comes from a suse 9.3 There seems to be a difference in schemas anyway. (opensuse 10.1 has openldap version 2.3.19 , 9.3 -> 2.2.23) I've get these errors during import -> structuralObjectClass 'posixGroup' is not STRUCTURAL The entry on which i've got the complaints ->

dn: cn=root,ou=Group,dc=deterp,dc=be objectClass: posixGroup objectClass: top cn: root userPassword:: xxxxxxx gidNumber: 0 structuralObjectClass: posixGroup

I did a search in the faq and on google, but didn't find very much about it.

jef peeraer