[Dovecot] Error: userdb lookup

[kfx]

Hi list,

I am trying to get rid of the "Error: 
file_dotlock_create(~/.dovecot.lda-dupes) failed: No such file or 
directory" by adding home directories to my virtual users (ldap).
I want this home dir' to be specified like this:
/var/vmail/$USER/home/
and the sieve scripts to go to:
/var/vmail/$USER/home/sieve/

So as suggested before in this list, I have replaced:
user_attrs = mailMessageStore=mail,mailQuotaSize=quota_rule=*:bytes=%$
by
user_attrs = mailMessageStore=mail,mailQuotaSize=quota_rule=*:bytes=%$, 
=home=/var/vmail/%u/home

But then the userdb lookup fail and it tells me this in the log:
deliver(user at mydomain): Error: userdb lookup: 
connect(/usr/local/var/run/dovecot/auth-master) failed: No such file or 
directory

This is strange because:
a. the socket is at /var/run/dovecot/auth-master
b. it is working flawlessly with the original user_attrs value

So I am thinking that this setting is totally ignored by dovecot at some 
point.

I must be missing something.
Any help please ?

My postfix's master.cf with the deliver relevant line:
dovecot   unix  -       n       n       -       -       pipe
  flags=DRhu user=vmail:vmail argv=/usr/local/libexec/dovecot/deliver -f 
${sender} -d ${recipient}

My postfix's main.cf with the deliver relevant line:
mailbox_command = /usr/local/libexec/dovecot/deliver


And my dovecot.conf and dovecot-ldap.conf:

# 1.2.4: /usr/local/etc/dovecot.conf
# OS: Linux 2.6.18-164.el5 x86_64 CentOS release 5.3 (Final) ext3
log_path: /var/log/dovecot-error.log
info_log_path: /var/log/dovecot-debug.log
protocols: imap imaps pop3 pop3s managesieve
ssl_ca_file: /etc/pki/CA/chaine.crt
ssl_cert_file: /etc/pki/dovecot/certs/mail.mydomain.pem
ssl_key_file: /etc/pki/dovecot/private/mail.mydomain.key
login_dir: /usr/local/var/run/dovecot/login
login_executable(default): /usr/local/libexec/dovecot/imap-login
login_executable(imap): /usr/local/libexec/dovecot/imap-login
login_executable(pop3): /usr/local/libexec/dovecot/pop3-login
login_executable(managesieve): /usr/local/libexec/dovecot/managesieve-login
login_greeting: Welcome
login_processes_count: 8
login_max_processes_count: 192
verbose_proctitle: yes
mail_uid: vmail
mail_gid: vmail
mail_location: maildir:/var/vmail/%n
mail_executable(default): /usr/local/libexec/dovecot/imap
mail_executable(imap): /usr/local/libexec/dovecot/imap
mail_executable(pop3): /usr/local/libexec/dovecot/pop3
mail_executable(managesieve): /usr/local/libexec/dovecot/managesieve
mail_plugins(default): quota imap_quota
mail_plugins(imap): quota imap_quota
mail_plugins(pop3): quota
mail_plugins(managesieve):
mail_plugin_dir(default): /usr/local/lib/dovecot/imap
mail_plugin_dir(imap): /usr/local/lib/dovecot/imap
mail_plugin_dir(pop3): /usr/local/lib/dovecot/pop3
mail_plugin_dir(managesieve): /usr/local/lib/dovecot/managesieve
imap_client_workarounds(default): outlook-idle
imap_client_workarounds(imap): outlook-idle
imap_client_workarounds(pop3):
imap_client_workarounds(managesieve):
lda:
  postmaster_address: postmaster at mydomain
  hostname: mydomain
  mail_plugins: quota sieve
auth default:
  username_format: %Ln
  passdb:
    driver: ldap
    args: /etc/dovecot-ldap.conf
  userdb:
    driver: ldap
    args: /etc/dovecot-ldap-userdb.conf
  socket:
    type: listen
    master:
      path: /var/run/dovecot/auth-master
      mode: 384
      user: vmail
      group: vmail
plugin:
  quota: maildir:User quota
  quota_rule: *:storage=10GB
  quota_rule2: Trash:storage=10%%
  sieve_dir: /var/vmail/%u/home/sieve
  sieve: /var/sieve-scripts/%u.sieve
##############################

dovecot-ldap.conf:

uris = ldaps://ldap.mydomain ldaps://ldap2.mydomain
tls = no
tls_ca_cert_file = /etc/pki/CA/chaine.crt
tls_require_cert = never
auth_bind = yes
auth_bind_userdn = uid=%u,ou=people,dc=mydomain
base = ou=people,dc=mydomain
user_attrs = mailMessageStore=mail,mailQuotaSize=quota_rule=*:bytes=%$
user_filter = (&(accountStatus=active)(uid=%n))
pass_filter = (&(accountStatus=active)(uid=%u))
########################################