overlay "syncprov" not found

[Jonathan Dobbie <jonathan_dobbie@mcad.edu>]

I'm trying to set up syncprov on Ubuntu's 2.4.7, but slaptest returns:

root@higgsboson:~# slaptest
overlay "syncprov" not found
slaptest: bad configuration file!

As far as I can tell, the module is there:

root@higgsboson:~# ls /usr/lib/ldap/syncprov*
/usr/lib/ldap/syncprov-2.4.so.2  /usr/lib/ldap/syncprov-2.4.so.2.0.3  / 
usr/lib/ldap/syncprov.la  /usr/lib/ldap/syncprov.so

Below is a slightly trimmed version of slapd.conf:

allow bind_v2
readonly off
include     /etc/ldap/schema/core.schema
include     /etc/ldap/schema/cosine.schema
include     /etc/ldap/schema/nis.schema
include     /etc/ldap/schema/inetorgperson.schema
include     /usr/local/etc/ldap/schema/samba.schema
include     /usr/local/etc/ldap/schema/apple.schema
include     /usr/local/etc/ldap/schema/mcadmail.schema
include     /usr/local/etc/ldap/schema/mcad.schema
include     /usr/local/etc/ldap/schema/mcad.radmind.schema
TLSCACertificateFile /etc/ldap/ssl/higgsboson.pem
TLSCertificateFile /etc/ldap/ssl/higgsboson.pem
TLSCertificateKeyFile /etc/ldap/ssl/higgsboson.pem
authz-regexp uid=([^,]*),cn=PLAIN,cn=auth uid= 
$1,dc=users,dc=accounts,dc=mcad,dc=edu
sasl-secprops none
pidfile         /var/run/slapd/slapd.pid
argsfile        /var/run/slapd/slapd.args
loglevel 128
threads 10
modulepath  /usr/lib/ldap
moduleload  back_bdb
defaultsearchbase  "dc=accounts,dc=ldap,dc=mcad,dc=edu"
idletimeout 600
password-hash {SSHA}
backend bdb
database        bdb
suffix          "dc=mcad,dc=edu"
checkpoint 512 30
cachesize 2000
idlcachesize 6000
directory       "/var/lib/ldap"
index   objectClass             eq
index   cn,sn,uid               pres,eq,approx,sub
index   givenName               eq,sub
index   displayName             eq,sub
index   mail,mailAlias          eq,sub
index   activePopImap           eq
index   activeSmtp              eq
index   ceridianID              eq
index   jenzabarID              eq
index   ou                      eq
index   employeeNumber          eq
index   employeeType            eq
index   uidNumber,gidNumber     eq
index   memberUid               eq
index   macAddress              eq
index   apple-generateduid      eq
index   apple-group-realname    eq
index   apple-computers         eq
index   apple-mcxflags          sub
index   apple-category          eq
index   apple-networkview       eq
index   apple-group-memberguid  eq
index   apple-group-nestedgroup eq
index   entryUUID               eq
index   entryCSN                eq
index   mailbox                 eq
overlay syncprov
syncprov-checkpoint 100 10
syncprov-sessionlog 100
lastmod         on


And then all of the ACLs