slapd crash with access_log overlay

[Alexander Kriventsov <akriventsov@masterhost.ru>]

Hello.
I have crash slapd when I create new node in MirrorMode.
After start slapd, it transfer database from master and after transfer all
entires it crash by signal 6. In slapd.conf I have
# log database
database        hdb
suffix          "cn=db-log"
rootdn          "cn=ldapadm,cn=db-log"
rootpw          {SSHA}PASS
directory       /var/db/openldap-data/db-log
checkpoint      32 8

# main database
database        hdb
suffix          "o=company"
rootdn          "cn=ldapadm,o=company"
rootpw          {SSHA}PASS
directory       /var/db/openldap-data/company
checkpoint      32 8

overlay         unique
unique_uri      ldap:///ou=users,o=company?uidNumber?sub

overlay         smbk5pwd
smbk5pwd-enable samba

overlay         accesslog
logdb           cn=db-log
logops          writes
logold          (objectClass=*)
logsuccess      false
logpurge        182+00:00 1+00:00

overlay         syncprov
syncprov-checkpoint     100 10
syncprov-sessionlog     100

syncrepl        rid=001
                provider=ldaps://ldap1
                bindmethod=simple
                binddn="uid=replication,ou=users,o=company"
                credentials=secret
                searchbase="o=company"
                schemachecking=on
                type=refreshAndPersist
                retry="60 +"

syncrepl        rid=002
                provider=ldaps://ldap2
                bindmethod=simple
                binddn="uid=replication,ou=users,o=company"
                credentials=secret
                searchbase="o=company"
                schemachecking=on
                type=refreshAndPersist
                retry="60 +"

mirrormode on

In logs I didn't find any information of crash.
Only in messages
ldap2 kernel: pid 5242 (slapd), uid 389: exited on signal 6

I didn't find any use full information in slapd.core
#0  0x000000080163bfec in thr_kill () from /lib/libc.so.7
[New Thread 0x802605850 (LWP 100246)]
[New Thread 0x8026056e0 (LWP 100244)]
[New Thread 0x802605570 (LWP 100233)]
[New Thread 0x802605400 (LWP 100225)]
[New Thread 0x802605290 (LWP 100216)]
[New Thread 0x802605120 (LWP 100096)]
[New Thread 0x801901850 (LWP 100081)]
[New Thread 0x801901120 (LWP 100240)]

System: FreeBSD 7.0-amd64-20080719-RELENG_7_0
Openldap: 2.4.11

In log I have
oc_check_allowed type "contextCSN"
=> entry_encode(0x00000001):
hdb_modify: updated id=00000001 dn="o=company"
send_ldap_result: conn=-1 op=0 p=0
send_ldap_result: err=0 matched="" text=""
slap_queue_csn: queing 0x8043ed160 20080812170512.000000Z#000000#000#000000
==> hdb_add: reqStart=20080814112242.000033Z,cn=db-log
Assertion failed: (a->a_vals[0].bv_val != NULL), function entry_schema_check, file schema_check.c, line 88.
Abort trap: 6 (core dumped)

Please advise.

-- 
Best Regards,
Alexander Kriventsov
.masterhost