Hi I am running Openldap 2.4.23 on RHEL6. I can telnet to the server on both 389 636 ports. I can do a ldapsearch and ldapadd without any errors. I get this error when I start the slapd daemon.
In addition to the issue noted by Rich, I would note that you are using an ancient release with numerous known issues that is not suitable for a production LDAP server. I would strongly advise you to use a current OpenLDAP release. If you do not feel comfortable building OpenLDAP yourself, there are packages available at <http://ltb-project.org/wiki/download#openldap> that should meet your needs.
--Quanah -- Quanah Gibson-Mount Sr. Member of Technical Staff Zimbra, Inc A Division of VMware, Inc. -------------------- Zimbra :: the leader in open source messaging and collaboration