[Dovecot] an intresting problem

[Mohsen Pahlevanzadeh]

Dear all,
I have compiled dovecot.When i use dovecot --build-options , i receive
following messages:
------------------------------------------------
debian:/home/mohsen# dovecot --build-options
Build options: ioloop=epoll notify=inotify ipv6 openssl
Mail storages: maildir mbox dbox cydir raw
SQL drivers:
Passdb: checkpassword vpopmail
Userdb: prefetch static vpopmail
-------------------------------------------------------
Also i have vpopmail & installed it to /home/vpopmail
I added joojoo domain. & postmaster at joojoo user.
When i use mysql vpopmail,and  use select
pw_domain,pw_name,pw_clear_password from vpopmail;
Then i see following message:
+------------+------------+-----------------+
| pw_domain  | pw_name    | pw_clear_passwd |
+------------+------------+-----------------+
| joojoo     | postmaster | 123456          | 
| final.com  | postmaster | 123456          | 
| janjan.com | postmaster | 123456          | 
| final.com  | mohsen     | 123456          | 
| final.com  | kamal      | 123456          | 
+------------+------------+-----------------+

When i use `telnet 0 110` i see following message plus my command:
debian:/home/mohsen# telnet 0 110
Trying 0.0.0.0...
Connected to 0.
Escape character is '^]'.
+OK Dovecot ready.
user postmaster at joojoo
+OK
pass 123456
-ERR Authentication failed.
^]
telnet> quit
Connection closed.
/////////////////////////
Then i see my log file & saw following messages:
//////////////////////////////////////////////////
dovecot: Mar 02 20:10:23 Info: auth(default): new auth connection:
pid=2657
dovecot: Mar 02 20:10:39 Info: auth(default): client in:
AUTH   1       PLAIN
service=pop3    secured lip=127.0.0.1   rip=127.0.0.1   lport=110       rport=38239
resp=AHBvc3RtYXN0ZXJAam9vam9vADEyMzQ1Ng==
dovecot: Mar 02 20:10:39 Info: auth(default):
checkpassword(postmaster at joojoo,127.0.0.1):
execute: /home/vpopmail/bin/vchkpw /usr/local/libexec/dovecot/checkpassword-reply
dovecot: Mar 02 20:10:39 Info: auth(default):
checkpassword(postmaster at joojoo,127.0.0.1): Received no input
dovecot: Mar 02 20:10:39 Info: auth(default):
checkpassword(postmaster at joojoo,127.0.0.1): exit_status=3
dovecot: Mar 02 20:10:39 Info: auth(default):
checkpassword(postmaster at joojoo,127.0.0.1): Login failed (status=3)
dovecot: Mar 02 20:10:39 Info: auth(default):
vpopmail(postmaster at joojoo,127.0.0.1): lookup user=postmaster
domain=joojoo
dovecot: Mar 02 20:10:39 Info: auth(default):
vpopmail(postmaster at joojoo,127.0.0.1): unknown user
dovecot: Mar 02 20:10:41 Info: auth(default): client out: FAIL  1
user=postmaster at joojoo
dovecot: Mar 02 20:10:53 Info: pop3-login: Disconnected (auth failed, 1
attempts): user=<postmaster at joojoo>, method=PLAIN, rip=127.0.0.1,
lip=127.0.0.1, secured
//////////////////////////////////////////////////
I use dovecot -n & saw following messages:
debian:/home/mohsen# dovecot -n
# 1.1.11: /usr/local/etc/dovecot.conf
# OS: Linux 2.6.26-1-486 i686 Debian 5.0 
log_path: /var/log/dovecot.log
info_log_path: /var/log/dovecot.info
protocols: pop3
ssl_disable: yes
disable_plaintext_auth: no
login_dir: /usr/local/var/run/dovecot/login
login_executable: /usr/local/libexec/dovecot/pop3-login
first_valid_uid: 89
last_valid_uid: 89
mail_uid: 89
mail_gid: 89
mail_location: maildir:~/Maildir
maildir_copy_preserve_filename: yes
mail_executable: /usr/local/libexec/dovecot/pop3
mail_plugin_dir: /usr/local/lib/dovecot/pop3
auth default:
  user: vpopmail
  verbose: yes
  debug: yes
  debug_passwords: yes
  passdb:
    driver: checkpassword
    args: /home/vpopmail/bin/vchkpw
  passdb:
    driver: vpopmail
    args: cache_key=%u%s *
  userdb:
    driver: vpopmail
debian:/home/mohsen# 
-------------------------------------
Please guide me.......