freeradius3 ldap module

[ferdinando]

hi all

im trying to make fr3 running with ldap support against samba4 but 
something goes wrong... i only need to check the ldap group membership 
of wifi user, defined in users file.
this is the log:
....
   # Instantiating module "ldap" from file 
/usr/local/app/freeradius-3.1.0/etc/raddb/mods-enabled/ldap
   ldap {
         server = "dc01.bunkertor.local"
         port = 389
         password = "Polo1976."
         identity = 
"CN=auth_radius,OU=services,OU=lan,DC=bunkertor,DC=local"
    user {
         filter = "(sAMAccountName=%{%{Stripped-User-Name}:-%{User-Name}})"
         scope = "sub"
         base_dn = "dc=bunkertor,dc=local"
         access_positive = yes
    }
    group {
         filter = "(objectClass=posixGroup)"
         scope = "sub"
         base_dn = "dc=bunkertor,dc=local"
         name_attribute = "cn"
         membership_attribute = "memberOf"
         membership_filter = 
"(|(member=%{control:Ldap-UserDn})(memberUid=%{%{Stripped-User-Name}:-%{User-Name}}))"
         cacheable_name = no
         cacheable_dn = no
    }
    client {
         filter = "(objectClass=frClient)"
         scope = "sub"
         base_dn = "dc=bunkertor,dc=local"
     attribute {
         identifier = "radiusClientIdentifier"
         shortname = "cn"
         secret = "radiusClientSecret"
     }
    }
    profile {
         filter = "(&)"
    }
    options {
         ldap_debug = 40
         chase_referrals = yes
         rebind = yes
         net_timeout = 1
         res_timeout = 20
         srv_timelimit = 20
         idle = 60
         probes = 3
         interval = 3
    }
    tls {
         start_tls = no
    }
   }
    accounting {
         reference = "%{tolower:type.%{Acct-Status-Type}}"
    }
    post-auth {
         reference = "."
    }
rlm_ldap (ldap): Initialising connection pool
    pool {
         start = 5
         min = 4
         max = 10
         spare = 3
         uses = 0
         lifetime = 0
         cleanup_delay = 5
         idle_timeout = 60
         spread = no
    }
rlm_ldap (ldap): Opening additional connection (0)
rlm_ldap (ldap): Opening connection failed (0)
rlm_ldap (ldap): Removing connection pool
/usr/local/app/freeradius-3.1.0/etc/raddb/mods-enabled/ldap[8]: 
Instantiation failed for module "ldap"
....
checking samba4 log i cannot see any connection attemps.

thats wierd, becouse:

root at radius:/usr/local/app/freeradius-3.1.0/sbin# ldapsearch -LLL -H 
ldap://dc01 -x -D 
'CN=auth_radius,OU=services,OU=lan,DC=bunkertor,DC=local' -w Polo1976. 
-b 'dc=bunkertor,dc=local' samaccountname=wifi_user
dn: CN=wifi_user,OU=users,OU=lan,DC=bunkertor,DC=local
objectClass: top
objectClass: person
objectClass: organizationalPerson
objectClass: user
cn: wifi_user
givenName: wifi_user
instanceType: 4
whenCreated: 20131011091034.0Z
displayName: wifi_user
uSNCreated: 4348
name: wifi_user
objectGUID:: 84lCIUpEDEK7C4g5/Zj9xA==
badPwdCount: 0
codePage: 0
countryCode: 0
badPasswordTime: 0
lastLogoff: 0
lastLogon: 0
primaryGroupID: 513
objectSid:: AQUAAAAAAAUVAAAAbnIRzvzJQRP8xGLfawQAAA==
accountExpires: 9223372036854775807
logonCount: 0
sAMAccountName: wifi_user
sAMAccountType: 805306368
userPrincipalName: wifi_user at bunkertor.local
objectCategory: CN=Person,CN=Schema,CN=Configuration,DC=bunkertor,DC=local
pwdLastSet: 130259562340000000
userAccountControl: 66048
memberOf: 
CN=grp_wifi,OU=service-groups,OU=groups,OU=lan,DC=bunkertor,DC=local
msSFU30NisDomain: bunkertor
uidNumber: 10010
loginShell: /bin/sh
unixHomeDirectory: /home/wifi_user
gidNumber: 3000022
msSFU30Name: wifi_user
uid: wifi_user
whenChanged: 20131011091113.0Z
uSNChanged: 4355
distinguishedName: CN=wifi_user,OU=users,OU=lan,DC=bunkertor,DC=local

# refldap://bunkertor.local/CN=Configuration,DC=bunkertor,DC=local

# refldap://bunkertor.local/DC=DomainDnsZones,DC=bunkertor,DC=local

# refldap://bunkertor.local/DC=ForestDnsZones,DC=bunkertor,DC=local
....

i cannot understand where is the mistake.... =(

thanks in advance for help.
bye.