[Dovecot] permisions problems to setup dovecot lda in postfix with sieve

[maximatt]

hi...

i can setup dovecot lda in postfix with sieve in testing enviroment using
dovecot 1.2.10 and dovecot-1.2-sieve-0.0.15

but now i want to setup them in producction so  i reproduce the steps to do
them but i receive the following errors:

log dovecot-deliver-errors.log:

Jul 29 11:48:26 deliver(xxxx at xxxx): Error: userdb lookup:
connect(/var/spool/postfix/private/auth-master) failed: Permission denied
(euid=500(xmail) egid=500(xmail) missing +x perm:
/var/spool/postfix/private)

log maillog:
:
:
Jul 29 15:19:33 xxxx postfix/pipe[18600]: deliver_request_get: file
active/7CF98168230
Jul 29 15:19:33 xxxx postfix/pipe[18600]: deliver_message: from
<xxxxx at xxxxxxxxx>
Jul 29 15:19:33 xxxx postfix/pipe[18600]: dict_eval: const
/etc/dovecot/libexec/deliver
Jul 29 15:19:33 xxxx postfix/pipe[18600]: dict_eval: const  -f
Jul 29 15:19:33 xxxx postfix/pipe[18600]: dict_eval: expand ${sender} ->
xxxxx at xxxxxxxx
Jul 29 15:19:33 xxxx postfix/pipe[18600]: dict_eval: const  -d
Jul 29 15:19:33 xxxx postfix/pipe[18600]: dict_eval: expand ${recipient} ->
xxxxxxx at xxxxxx
Jul 29 15:19:33 xxxx postfix/pipe[18600]: connect to subsystem private/defer
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr nrequest = 0
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr flags = 0
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr queue_id = 7CF98168230
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr original_recipient =
xxxxxx at xxxxxxx
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr recipient = xxxxx at xxxxx
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr offset = 4294967295
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr dsn_orig_rcpt =
rfc822;xxxxxxx at xxxxxxxx
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr notify_flags = 0
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr status = 4.3.0
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr diag_type = x-unix
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr diag_text = temporary
failure
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr mta_type =
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr mta_mname =
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr action = delayed
Jul 29 15:19:33 xxxx postfix/pipe[18600]: send attr reason = temporary
failure
Jul 29 15:19:33 xxxx postfix/pipe[18600]: private/defer socket: wanted
attribute: status
Jul 29 15:19:33 xxxx postfix/pipe[18600]: input attribute name: status
Jul 29 15:19:33 xxxx postfix/pipe[18600]: input attribute value: 0
Jul 29 15:19:33 xxxx postfix/pipe[18600]: private/defer socket: wanted
attribute: (list terminator)
Jul 29 15:19:33 xxxx postfix/pipe[18600]: input attribute name: (end)
Jul 29 15:19:33 xxxx postfix/pipe[18600]: 7CF98168230: to=<xxxxx at xxxxxxx>,
relay=dovecot, delay=0.24, delays=0.2/0.01/0/0.03, dsn=4.3.0,
status=deferred (temporary failure)
:
:

these are the configurations that i set:

config in dovecot:
# 1.2.10: /etc/dovecot/dovecot.conf
# OS: Linux 2.6.9-67.0.4.ELsmp i686 CentOS 4
:
:
lda:
  postmaster_address: postmaster at xxxxxx
  mail_plugins: sieve
  auth_socket_path: /var/spool/postfix/private/auth-master
  log_path: /var/log/dovecot-deliver-errors.log
  info_log_path: /var/log/dovecot-deliver.log
auth default:
  :
  :
  passdb:
    driver: ldap
    args: /etc/dovecot/dovecot-ldap.conf
  userdb:
    driver: ldap
    args: /etc/dovecot/dovecot-ldap.conf
  userdb:
    driver: nss
    args: service=ldap blocking=yes
  socket:
    type: listen
    client:
      path: /var/spool/postfix/private/authldap
      mode: 432
      user: postfix
      group: postdrop
    master:
      path: /var/spool/postfix/private/auth-master
      mode: 432
      user: xmail
      group: xmail
plugin:
  sieve: /etc/dovecot/sieve/scripts/%n.sieve
  sieve_global_dir: /etc/dovecot/sieve/scripts/
  sieve_global_path: /etc/dovecot/sieve/scripts/default.sieve
  sieve_after: /etc/dovecot/sieve/scripts/default.sieve

i cannot set the apropiate permisions without broke the service... and i
cant find the mistake yet... :(
¿whats could be happend? :(

Thanks in advance!

-- 
*Salu2 ;)*