shared folders

[Scherff]

Hi,
i am stuck. Try to install shared folders - dovecot is running fine. ACL 
is working. But i can't get running the shared folders. Maybe someone 
can help.

This are the relevant conf. I think i have some mistake there - perhaps 
in location - changed try and error - stuck:

mail_home = /var/vmail/mailboxes/%d/%n
mail_location = maildir:~/mail:LAYOUT=fs

namespace {
  hidden = no
  ignore_on_failure = no
  list = children
  location = 
maildir:%%h/mail:INDEX=%h/mail/shared/%%u:CONTROL=%h/mail/shared/%%u
  prefix = shared/%%u/
  separator = /
  subscriptions = yes
  type = shared
}
namespace inbox {
  inbox = yes
  location =
  mailbox Archives {
    auto = subscribe
    special_use = \Archive
  }
  mailbox Drafts {
    auto = subscribe
    special_use = \Drafts
  }
  mailbox Notes {
    auto = subscribe
  }
  mailbox Sent {
    auto = subscribe
    special_use = \Sent
  }
  mailbox Spam {
    auto = subscribe
    special_use = \Junk
  }
  mailbox Trash {
    auto = subscribe
    special_use = \Trash
  }
  prefix =
}

plugin {
    # global acl - prevent expunche for some folder
     acl = vfile:/var/vmail/dovecot-acl
      acl_shared_dict = file:/var/vmail/db/shared-mailboxes.db
}

protocol imap {
  imap_idle_notify_interval = 15 mins
  mail_max_userip_connections = 30
  mail_plugins = " acl imap_acl"
}

protocol lmtp {
  mail_plugins = " acl"
}


Need some hint.

Thanks
Alfred