[Dovecot] public folders fchown error

[junk at mc1.mccarthy.ac]

I was hoping this would be the right place to look for some help, I cannot
make public folders get the right permissions.  I continually get the
fchown error in logs, and have googled high an low to find multiple
solutions that do not work for me.

I'm using maildir.  I have sendmail with postfix distributing my mail.  I
created maildir's in each users personal directory.  I then thought it
would be neat to set up a public folder that people could dump spam and
ham into, then have a cron script go through the directory and
automatically sort it for bayes.  However, when I put a file in the public
folder, the permissions do not seem to work.

I've put a dovecot-shared file with root.mail permissions, 660, in just
about every directory (all the public folder directories, and every
personal user's control and index location), I've chmod'd to 777 each file
and folder to test, etc, and no matter what, the dovecot.index.tmp in the
user's index folder comes through with their permissions, and this error
shows up.

Am I thinking this is something different then what it is or am I
completely off base?

Thanks in advance,
Bob

dovecot 1.0.13 (debian install)

# 1.0.13: /etc/dovecot/dovecot.conf
log_timestamp: %Y-%m-%d %H:%M:%S
protocols: imap imaps pop3 pop3s
login_dir: /var/run/dovecot/login
login_executable(default): /usr/lib/dovecot/imap-login
login_executable(imap): /usr/lib/dovecot/imap-login
login_executable(pop3): /usr/lib/dovecot/pop3-login
mail_privileged_group: mail
mail_location: maildir:/home/%u/Mail/Inbox
umask: 7
mail_executable(default): /usr/lib/dovecot/imap
mail_executable(imap): /usr/lib/dovecot/imap
mail_executable(pop3): /usr/lib/dovecot/pop3
mail_plugin_dir(default): /usr/lib/dovecot/modules/imap
mail_plugin_dir(imap): /usr/lib/dovecot/modules/imap
mail_plugin_dir(pop3): /usr/lib/dovecot/modules/pop3
pop3_uidl_format(default):
pop3_uidl_format(imap):
pop3_uidl_format(pop3): %08Xu%08Xv
namespace:
  type: public
  separator: /
  prefix: Public/
  location:
maildir:/var/mail/public:CONTROL=~/Mail/public/public:INDEX=~/Mail/public/index
namespace:
  type: private
  separator: /
  inbox: yes
auth default:
  mechanisms: plain login
  passdb:
    driver: pam
  userdb:
    driver: passwd