[Dovecot] Problem with Courier POP3 Migration to dovecot POP3

[Ashraf]

Hi Timo/all
   Help me please, i am in the process of migrating courier to dovecot
1.1.14. I want to do migration as users loging so i am using this script *
http://www.dovecot.org/tools/courier-dovecot-migrate.pl *,
When i do use post-logging script to migrate* POP3*, its downloading
messages again (*Duplicating messages)* , as some of our users prefer to
leave messages on server. If i run the script manually on particular users
home directory and try to download it *still duplicating messages, *as its
creating whole new set of dovecot files.
*
*
About my environment

     -- MailDir's stored in NFS location
     -- User Authenticated using MySQL


 my dovecot.conf looks like

base_dir = /var/run/dovecot/
protocols = imap pop3
listen = *, [::]
log_path =/var/log/dovecot.log
info_log_path = /var/log/dovecot-info.log
ssl_disable = yes
login_process_per_connection = no
login_processes_count = 10
login_max_processes_count = 128
login_max_connections = 256
login_greeting = Dovecot ready.
mail_location = maildir:~/
mail_debug = yes
mmap_disable = yes
dotlock_use_excl = yes
mail_nfs_index = yes
lock_method = dotlock
mail_drop_priv_before_exec = yes
first_valid_uid = 195
max_mail_processes = 512
mail_process_size = 256
mailbox_idle_check_interval = 20
protocol imap {
}

protocol pop3 {
  *mail_executable = /usr/libexec/dovecot/postpop3.sh*
  mail_max_userip_connections = 10
  pop3_client_workarounds = outlook-no-nuls oe-ns-eoh
}
auth_verbose = yes
auth_debug = yes
auth default {
  mechanisms = plain
  passdb sql {
    args = /etc/dovecot-mysql.conf
  }
  userdb sql {
    args = /etc/dovecot-mysql.conf
  }
  user = root
}

dict {
}

plugin {

}


----
my postloggin script --

$ cat /usr/libexec/dovecot/postpop3.sh

#!/bin/sh
# WARNING: Be sure to use mail_drop_priv_before_exec=yes,
# otherwise the files are created as root!
/usr/libexec/dovecot/courier-dovecot-migrate.pl --quiet --to-dovecot
--recursive --convert  ${HOME}
# This is for pop3
exec /usr/libexec/dovecot/pop3

----

Please advise am i doing something wrong, please guide me, let me know if
you need any more info about my setup.

-- 
Regards
Ashraf