During the OES install, there's a section called "LDAP Configuration for Open Enterprise Services" where you're asked to provide the IP address(es) of "Configured LDAP Servers."

But in the comments to the left, it says to enter a server with "either the master or a read/write replica of the eDirectory tree."

So which does it want: an eDirectory server, or an LDAP server?

Because in our (still primarily NetWare) environment, they aren't the same. We have NetWare servers for holding eDirectory replicas. And we have different NetWare servers for answering LDAP requests.