The "easy" fix is here
ftp://ftp.openldap.org/incoming/pierangelo-masarati-2010-02-21-dontusecopy-otp.patch
I haven't committed it (needs some polishing) because it touches slapo-chain(5) in a couple of places, and I'd rather be sure it does not break anything. I won't be able to work at it for a while. It needs some polishing (SASL attributes that may need dontUseCopy should be at least configurable and so).
Please test.