I found reason of this error. I should compile openldap with --enable-unique. But it is very strange to get this error instead of "error: overlay unique is not active". Thanks to all.
File an ITS at <http://www.openldap.org/its/>
--Quanah
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Quanah Gibson-Mount Principal Software Engineer Zimbra, Inc -------------------- Zimbra :: the leader in open source messaging and collaboration