[Exim] LDAP search: no results

I'm in the process of converting one of my servers from NIS+ lookups to
LDAP but I'm having problems with the lookup. This is with Exim 3.22

My director:

localuser:
driver = aliasfile
search_type = ldap
query = "user=\ldapuser\" ldap:///o=domain.com,ou=People?uid?sub?(uid=$local_part)"
group = user
transport = local_delivery

an exim -d9 -bt twells@??? returns:

localuser director: ldap query=user="ldapuser"
ldap:///o=domain.com,ou=People?uid?sub?(uid=twells)
search_open: ldap "NULL"
search_find: file="NULL"
key="user="ldapuser"
ldap:///o=domain.com,ou=People?uid?sub?(uid=twells)" partial=-1
LRU list:
7/etc/aliases
End
internal_search_find: file="NULL"
type=ldap key="user="ldapuser"
ldap:///o=domain.com,ou=People?uid?sub?(uid=twells)"
database lookup required for user="ldapuser"
ldap:///o=domain.com,ou=People?uid?sub?(uid=twells)
LDAP parameters: user=ldapuser pass=NULL size=0 time=0
perform_ldap_search: ldap URL="ldap:///o=domain.com,ou=People?uid?sub?(uid=twells)"
server=ldap1.domain.com
port=389 sizelimit=0 timelimit=0
Opened connection to LDAP server ldap1.domain.com:389
Binding with user=ldapuser password=NULL
Start search
search ended by ldap_result yielding 101
LDAP search: no results
lookup failed
localuser director declined for twells: LDAP search: no results
twells@??? is undeliverable:
unknown local-part "twells" in domain "pop.domain.com"
search_tidyup called
unbind LDAP connection to ldap1.domain.com:389

My users look like:

ldapsearch -h ldap1.domain.com -b o=domain.com -D "cn=ldapuser" uid=twells
version: 2

#
# filter: uid=twells
# requesting: ALL
#

# twells,People,domain.com
dn: uid=twells,ou=People,o=domain.com
uid: twells
cn: tabor wells
givenname: tabor
sn: wells
objectclass: person
objectclass: organizationalPerson
objectclass: inetOrgPerson
objectclass: account
objectclass: posixAccount
objectclass: shadowAccount
objectclass: ntUser
objectclass: top
loginshell: /bin/tcsh
uidnumber: XXX
gidnumber: XXX
homedirectory: /home/twells
gecos: tabor wells
ntuserdomainid: XXXXXX

# search result
search: 2
result: 0 Success

# numResponses: 2
# numEntries: 1

Any suggestions about what I'm doing wrong here?

Thanks,

Tabor

-- 
--------------------------------------------------------------------
Tabor J. Wells                                     twells@???
Fsck It!                 Just another victim of the ambient morality