ldap_add: Constraint violation (19)
How did you generate those LDIF files? structuralObjectClass is one of the internal values in OpenLDAP and user - even administrator - cannot normally modify those.
Either remove those structuralObjectClass lines from your LDIF or import the entries back with slapadd (I bet you generated the LDIF files with slapcat).
you need delete the following lines in the ldif file:
structuralObjectClass:
entryUUID:
creatorsName:
createTimestamp:
entryCSN:
modifiersName:
modifyTimestamp: