Quoting Quanah Gibson-Mount <quanah@zimbra.com>:
... He is probably missing having it configured as a backend entirely.
That wasn't literally his question, but I would not be surprised if Dan was right. I've been running Debian squeeze since June and started with a slapd.conf configuration. Then along came 2.4.23-3 and asked if I wanted to migrate to cn=config. I felt optimistic and said Yes. Doh! It failed. I forget exactly why; I'm very dependent on my slapd server and just wanted to get the old version running again ASAP.
Since then I've installed the new version many times, but have yet to go back and attempt that migration again. For some time now I've been wanting to set up a test system to see if I run into the same problem, and if so how to deal with it, but have yet to get around to it.
Cheers, Jaap