I'm using Openldap 2.3.43-3.el5 with BDB 4.3.29 on CentOS 5.3.
This is not a supported configuration. OpenLDAP has specifically not allowed compilation against BDB 4.3.29 for quite some time, due to its unreliability.
Using the "checkpoint" directive in slapd.conf/cn=config is what is supported, and is known to work if you use an actual supported version of BDB with OpenLDAP.
I suggest buying RHEL, and filing a bug with the RedHat folks for deliberately mucking with the OpenLDAP configure and bypassing a safeguard put into place by the OpenLDAP project. This is a RedHat inflicted issue, and not anything the OpenLDAP project can help you with.
Alternatively, build OpenLDAP yourself against a supported BDB release. I'd suggest OpenLDAP 2.4.18 with BDB 4.7.25+patches or BDB 4.8.
--Quanah -- Quanah Gibson-Mount Principal Software Engineer Zimbra, Inc -------------------- Zimbra :: the leader in open source messaging and collaboration