[otrs] Customer Users <-> Services not working

Hi, list: I'm using Postgres 8.1 and LDAP backend for both users and clients, and my environment seems to be working fine except it seems I can't add clients to services. Yes, Services are enabled through Core::Ticket::Service. It seems to be a problem with my database schema, since postgres logs shows the following: "ERROR: not allowed relationship service_customer_user" Any hint?