[Dovecot] "No such file or directory" error setting up dict quota for mdbox

[ADRIAN SANTOS MARRERO]

Hi, I've some troubles setting up the dict based quota plugin for mdbox, it
always returns a error when lmtp tries to deliver an e-mail:

Apr  8 12:40:16 mb07 dovecot: lmtp(3001, asmarre at ull.es): Error:
fstat(/sharedfs/10.4.1.107/ull.es/54/asmarre/dovecot-quota.lock) failed: No
such file or directory
Apr  8 12:40:16 mb07 dovecot: lmtp(3001, asmarre at ull.es): Error: file dict
commit: file_dotlock_open(/sharedfs/
10.4.1.107/ull.es/54/asmarre/dovecot-quota) failed: No such file or
directory
Apr  8 12:40:16 mb07 dovecot: lmtp(3001, asmarre at ull.es): Error: dict
quota: Quota update failed, it's now desynced

In fact lmtp does create the dovecot-quota.lock file but it does not update
the dovecot-quota file.

If I run "doveadm quota recalc -u asmarre" it works and updates the
dovecot-quota file.

The version of dovecot that I'm using is 2.0.19 and the configuration is:

# 2.0.19: /etc/dovecot/dovecot.conf
# OS: Linux 3.2.0-32-generic x86_64 Ubuntu 12.04.2 LTS
mail_debug = yes
mail_location = mdbox:%h
mail_plugins = quota
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope encoded-character
vacation subaddress comparator-i;ascii-numeric relational regex imap4flags
copy include variables body enotify environment mailbox date ihave
passdb {
  args = /etc/dovecot/dovecot-ldap.conf.ext
  driver = ldap
}
plugin {
  quota = dict:User quota::file:%h/dovecot-quota
  quota_rule = *:storage=1G
  quota_warning = storage=95%% quota-warning 95
  quota_warning2 = storage=85%% quota-warning 85
  sieve = ~/.dovecot.sieve
  sieve_dir = ~/sieve
}
postmaster_address = postmaster at ull.es
protocols = " imap lmtp sieve pop3"
service lmtp {
  inet_listener lmtp {
    port = 24
  }
}
service managesieve-login {
  inet_listener sieve_deprecated {
    port = 2000
  }
}
service quota-warning {
  executable = script /opt/ccti/correo/buzones/quota_warning.sh
  unix_listener quota-warning {
    user = dovecot
  }
  user = dovecot
}
ssl_cert = </etc/ssl/certs/www.ull.es.chain.crt
ssl_key = </etc/ssl/private/www.ull.es.key
userdb {
  args = /etc/dovecot/dovecot-ldap.conf.ext
  driver = ldap
}
protocol lmtp {
  mail_plugins = quota sieve zlib
}
protocol imap {
  mail_plugins = quota imap_quota
}
protocol pop3 {
  pop3_no_flag_updates = yes
  pop3_uidl_format = %v.%u
}

Thanks in advance.