[Dovecot] Deliver setgid failed: Operation not permitted

[Blake Carver]

Hi all, I'm having trouble getting a new Postfix/Dovecot server up and running.

I'm trying to run v1.0.3, using MySQL tables setup list postfix admin.
This is a RHEL5 server.
Getting this error
tail /var/log/dovecot/dovecot-deliver.log
deliver(none at example.com): Sep 04 19:44:15 Fatal: setgid(12) failed:
Operation not permitted
That 12 being my vmail user.

I'm not exactly sure what's trying to setgid, nor how to fix it, any
ideas would be appreciated.

Dovecot -n is below

protocols: imap imaps pop3 pop3s
ssl_disable: yes
disable_plaintext_auth: no
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
first_valid_uid: 101
last_valid_uid: 101
mail_extra_groups: mail
mail_location: maildir:/home/vmail/%d/%u
maildir_copy_with_hardlinks: yes
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_plugins(default): quota imap_quota
mail_plugins(imap): quota imap_quota
mail_plugins(pop3): quota
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
imap_client_workarounds(default): outlook-idle delay-newmail
imap_client_workarounds(imap): outlook-idle delay-newmail
imap_client_workarounds(pop3): outlook-idle
pop3_uidl_format(default):
pop3_uidl_format(imap):
pop3_uidl_format(pop3): %08Xu%08Xv
pop3_client_workarounds(default):
pop3_client_workarounds(imap):
pop3_client_workarounds(pop3): outlook-no-nuls oe-ns-eoh
auth default:
  verbose: yes
  debug: yes
  debug_passwords: yes
  passdb:
    driver: sql
    args: /etc/dovecot/sql.conf
  userdb:
    driver: sql
    args: /etc/dovecot/sql.conf
  socket:
    type: listen
    client:
      path: /var/spool/postfix/private/auth
      mode: 432
      user: postfix
      group: mail
    master:
      path: /var/run/dovecot/auth-master
      mode: 432
      user: vmail
      group: mail
plugin:
  quota: maildir:storage=10240:messages=1000
  acl: vfile:/etc/dovecot/acls
  trash: /etc/dovecot/trash.conf


--------------
Blake Carver
LISHost.org
Web Hosting For Librarians
http://www.lishost.org