you should add something like in your config.tcl:
ns_section "ns/ldap/pool/ldap"
ns_param user "cn=Manager, o=My LDAP"
ns_param password "password..."
ns_param host "ldapdev.server.edu"
ns_param connections 1
ns_param verbose On
#
# ldap pools
#
ns_section "ns/ldap/pools"
ns_param ldap ldap
#
# ldap default pool
#
ns_section "ns/server/${server}/ldap"
ns_param Pools *
ns_param DefaultPool ldap
more here:
http://www.galileo.edu/obonilla/software/nsldap