Thanks for your reply Zhang!
Sections from /var/logs/mail.log:
Oct 14 18:06:19 mail amavis[957]: No decoder for .tnef
Oct 14 18:06:19 mail amavis[957]: Internal decoder for .tnef
Oct 14 18:06:19 mail amavis[957]: No decoder for .exe tried: unrar-free; arj, unarj
Oct 14 18:06:19 mail amavis[957]: Using primary internal av scanner code for ClamAV-clamd
Oct 14 18:06:19 mail amavis[957]: Found secondary av scanner ClamAV-clamscan at /usr/bin/clamscan
Oct 14 18:06:19 mail amavis[957]: Creating db in /var/lib/amavis/db/; BerkeleyDB 0.39, libdb 4.8
Oct 14 18:06:33 mail postfix/master[1424]: daemon started -- version 2.7.0, configuration /etc/postfix
Oct 14 18:09:09 mail roundcube: [14-Oct-2010 18:09:09 +0200]: IMAP Error: Authentication for www@address.se failed (LOGIN): "a001 NO [UNAVAILABLE] Temporary authentication failure." (POST /mail/?_task=&_action=login)
Oct 14 18:39:58 mail roundcube: [14-Oct-2010 18:39:58 +0200]: IMAP Error: Authentication for www@address.se failed (LOGIN): "a001 NO [UNAVAILABLE] Temporary authentication failure." (POST /mail/?_task=&_action=login)
Oct 14 18:56:33 mail postfix/qmgr[1444]: 863EEA9F76: from=<root@mail.localdomain>, size=6369, nrcpt=1 (queue active)
Oct 14 18:56:34 mail postfix/qmgr[1444]: 94C9EA9F6E: from=<root@mail.localdomain>, size=1137, nrcpt=1 (queue active)
Oct 14 18:56:54 mail postfix/smtp[1785]: 94C9EA9F6E: to=<www@address.se>, relay=none, delay=6048, delays=6027/0.11/20/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=address.se type=MX: Host not found, try again)
Oct 14 18:56:54 mail postfix/smtp[1784]: 863EEA9F76: to=<www@address.se>, relay=none, delay=6048, delays=6027/0.29/20/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=address.se type=MX: Host not found, try again)
Oct 14 19:00:56 mail amavis[797]: starting. /usr/sbin/amavisd-new at mail.address.se amavisd-new-2.6.4 (20090625), Unicode aware
Oct 14 19:00:56 mail amavis[797]: Perl version 5.010001
Oct 14 19:00:57 mail amavis[960]: Net::Server: Group Not Defined. Defaulting to EGID '116 116'
Oct 14 19:00:57 mail amavis[960]: Net::Server: User Not Defined. Defaulting to EUID '107'
Oct 15 06:35:26 mail postfix/local[3220]: fatal: open database /etc/aliases.db: No such file or directory
Oct 15 06:35:27 mail postfix/master[1427]: warning: process /usr/lib/postfix/local pid 3220 exit status 1
Oct 15 06:35:27 mail postfix/master[1427]: warning: /usr/lib/postfix/local: bad command startup -- throttling
Oct 15 06:36:13 mail postfix/qmgr[1459]: 863EEA9F76: from=<root@mail.localdomain>, size=6369, nrcpt=1 (queue active)
Oct 15 06:36:13 mail postfix/qmgr[1459]: 94C9EA9F6E: from=<root@mail.localdomain>, size=1137, nrcpt=1 (queue active)
Oct 15 06:36:27 mail postfix/local[3225]: fatal: open database /etc/aliases.db: No such file or directory
Oct 15 06:36:28 mail postfix/master[1427]: warning: process /usr/lib/postfix/local pid 3225 exit status 1
Oct 15 06:36:28 mail postfix/master[1427]: warning: /usr/lib/postfix/local: bad command startup -- throttling
Oct 15 06:36:34 mail postfix/smtp[3223]: 863EEA9F76: to=<www@address.se>, relay=none, delay=48028, delays=48008/0.02/20/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=address.se type=MX: Host not found, try again)
Oct 15 06:36:34 mail postfix/smtp[3224]: 94C9EA9F6E: to=<www@address.se>, relay=none, delay=48028, delays=48007/0.02/20/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=address.se type=MX: Host not found, try again)
Oct 15 06:37:28 mail postfix/local[3228]: fatal: open database /etc/aliases.db: No such file or directory
Oct 15 06:37:29 mail postfix/master[1427]: warning: process /usr/lib/postfix/local pid 3228 exit status 1
Oct 15 06:37:29 mail postfix/master[1427]: warning: /usr/lib/postfix/local: bad command startup -- throttling
Oct 15 06:38:29 mail postfix/local[3229]: fatal: open database /etc/aliases.db: No such file or directory
Oct 15 06:38:30 mail postfix/master[1427]: warning: process /usr/lib/postfix/local pid 3229 exit status 1
Oct 15 06:38:30 mail postfix/master[1427]: warning: /usr/lib/postfix/local: bad command startup -- throttling
Oct 15 06:39:30 mail postfix/local[3239]: fatal: open database /etc/aliases.db: No such file or directory
Oct 15 06:39:31 mail postfix/master[1427]: warning: process /usr/lib/postfix/local pid 3239 exit status 1
Oct 15 07:44:34 mail postfix/local[3339]: fatal: open database /etc/aliases.db: No such file or directory
Oct 15 07:44:35 mail postfix/master[1427]: warning: process /usr/lib/postfix/local pid 3339 exit status 1
Oct 15 07:44:35 mail postfix/master[1427]: warning: /usr/lib/postfix/local: bad command startup -- throttling
Oct 15 07:45:35 mail postfix/local[3340]: fatal: open database /etc/aliases.db: No such file or directory
Oct 15 07:45:36 mail postfix/master[1427]: warning: process /usr/lib/postfix/local pid 3340 exit status 1
Oct 15 07:45:36 mail postfix/master[1427]: warning: /usr/lib/postfix/local: bad command startup -- throttling
Oct 15 07:46:13 mail postfix/qmgr[1459]: 863EEA9F76: from=<root@mail.localdomain>, size=6369, nrcpt=1 (queue active)
Oct 15 07:46:13 mail postfix/qmgr[1459]: 94C9EA9F6E: from=<root@mail.localdomain>, size=1137, nrcpt=1 (queue active)
Oct 15 07:46:33 mail postfix/smtp[3342]: 863EEA9F76: to=<www@address.se>, relay=none, delay=52227, delays=52207/0.02/20/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=address.se type=MX: Host not found, try again)
Oct 15 07:46:33 mail postfix/smtp[3343]: 94C9EA9F6E: to=<www@address.se>, relay=none, delay=52227, delays=52207/0.02/20/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=address.se type=MX: Host not found, try again)
Oct 15 07:46:36 mail postfix/local[3346]: fatal: open database /etc/aliases.db: No such file or directory
Oct 15 07:46:37 mail postfix/master[1427]: warning: process /usr/lib/postfix/local pid 3346 exit status 1
Oct 15 07:46:37 mail postfix/master[1427]: warning: /usr/lib/postfix/local: bad command startup -- throttling
Oct 15 07:47:37 mail postfix/local[3347]: fatal: open database /etc/aliases.db: No such file or directory
And this is the whole /var/logs/dovcote.log:
Oct 14 17:15:46 dovecot: Info: Dovecot v1.2.9 starting up (core dumps disabled)
Oct 14 17:15:46 auth-worker(default): Error: mysql: Connect failed to localhost (vmail): Access denied for user 'vmail'@'localhost' (using password: YES) - waiting for 1 seconds before retry
Oct 14 17:17:34 auth-worker(default): Error: mysql: Connect failed to localhost (vmail): Access denied for user 'vmail'@'localhost' (using password: YES) - waiting for 5 seconds before retry
Oct 14 17:17:34 auth-worker(default): Error: sql(www@address.e,127.0.0.1): Password query failed: Not connected to database
Oct 14 17:17:41 imap-login: Info: Disconnected (auth failed, 1 attempts): user=<www@address.e>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
Oct 14 17:37:58 dovecot: Warning: Killed with signal 15 (by pid=13018 uid=0 code=kill)
Oct 14 17:37:58 imap-login: Warning: Killed with signal 15 (by pid=13018 uid=0 code=kill)
Oct 14 17:37:58 auth-worker(default): Warning: Killed with signal 15 (by pid=13018 uid=0 code=kill)
Oct 14 17:37:58 auth(default): Warning: Killed with signal 15 (by pid=13018 uid=0 code=kill)
Oct 14 17:39:05 dovecot: Info: Dovecot v1.2.9 starting up (core dumps disabled)
Oct 14 17:39:05 auth-worker(default): Error: mysql: Connect failed to localhost (vmail): Access denied for user 'vmail'@'localhost' (using password: YES) - waiting for 1 seconds before retry
Oct 14 17:41:36 auth-worker(default): Error: mysql: Connect failed to localhost (vmail): Access denied for user 'vmail'@'localhost' (using password: YES) - waiting for 5 seconds before retry
Oct 14 17:41:36 auth-worker(default): Error: sql(postmaster@address.se,127.0.0.1): Password query failed: Not connected to database
Oct 14 17:41:43 imap-login: Info: Disconnected (auth failed, 1 attempts): user=<postmaster@address.se>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
Oct 14 17:41:50 auth-worker(default): Error: sql(www@address.se,127.0.0.1): Password query failed: Not connected to database
Oct 14 17:41:57 imap-login: Info: Disconnected (auth failed, 1 attempts): user=<www@address.se>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
Oct 14 17:46:28 auth-worker(default): Error: mysql: Connect failed to localhost (vmail): Access denied for user 'vmail'@'localhost' (using password: YES) - waiting for 75 seconds before retry
Oct 14 17:46:28 auth-worker(default): Error: sql(www@address.se,127.0.0.1): Password query failed: Not connected to database
Oct 14 17:46:35 imap-login: Info: Disconnected (auth failed, 1 attempts): user=<www@address.se>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
Oct 14 18:05:30 auth(default): Warning: Killed with signal 15 (by pid=2695 uid=0 code=kill)
Oct 14 18:05:30 pop3-login: Warning: Killed with signal 15 (by pid=2695 uid=0 code=kill)
Oct 14 18:05:30 pop3-login: Warning: Killed with signal 15 (by pid=2695 uid=0 code=kill)
Oct 14 18:05:30 managesieve-login: Warning: Killed with signal 15 (by pid=2695 uid=0 code=kill)
Oct 14 18:05:30 managesieve-login: Warning: Killed with signal 15 (by pid=2695 uid=0 code=kill)
Oct 14 18:05:30 imap-login: Warning: Killed with signal 15 (by pid=2695 uid=0 code=kill)
Oct 14 18:05:30 imap-login: Warning: Killed with signal 15 (by pid=2695 uid=0 code=kill)
Oct 14 18:05:30 auth-worker(default): Warning: Killed with signal 15 (by pid=2695 uid=0 code=kill)
Oct 14 18:05:30 managesieve-login: Warning: Killed with signal 15 (by pid=2695 uid=0 code=kill)
Oct 14 18:05:30 dovecot: Warning: Killed with signal 15 (by pid=2695 uid=0 code=kill)
Oct 14 18:05:30 pop3-login: Warning: Killed with signal 15 (by pid=2695 uid=0 code=kill)
Oct 14 18:05:30 dovecot: Warning: I/O leak: 0x7ff80f92a470 (21)
Oct 14 18:06:34 dovecot: Info: Dovecot v1.2.9 starting up (core dumps disabled)
Oct 14 18:06:34 auth-worker(default): Error: mysql: Connect failed to localhost (vmail): Access denied for user 'vmail'@'localhost' (using password: YES) - waiting for 1 seconds before retry
Oct 14 18:09:07 auth-worker(default): Error: mysql: Connect failed to localhost (vmail): Access denied for user 'vmail'@'localhost' (using password: YES) - waiting for 5 seconds before retry
Oct 14 18:09:07 auth-worker(default): Error: sql(www@address.se,127.0.0.1): Password query failed: Not connected to database
Oct 14 18:09:14 imap-login: Info: Disconnected (auth failed, 1 attempts): user=<www@address.se>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
Oct 14 18:39:56 auth-worker(default): Error: mysql: Connect failed to localhost (vmail): Access denied for user 'vmail'@'localhost' (using password: YES) - waiting for 75 seconds before retry
Oct 14 18:39:56 auth-worker(default): Error: sql(www@address.se,127.0.0.1): Password query failed: Not connected to database
Oct 14 18:40:03 imap-login: Info: Disconnected (auth failed, 1 attempts): user=<www@address.se>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured
Oct 14 19:00:02 dovecot: Warning: Killed with signal 15 (by pid=2295 uid=0 code=kill)
Oct 14 19:00:02 managesieve-login: Warning: Killed with signal 15 (by pid=2295 uid=0 code=kill)
Oct 14 19:00:02 auth-worker(default): Warning: Killed with signal 15 (by pid=2295 uid=0 code=kill)
Oct 14 19:01:13 dovecot: Info: Dovecot v1.2.9 starting up (core dumps disabled)
Oct 14 19:01:13 auth-worker(default): Error: mysql: Connect failed to localhost (vmail): Access denied for user 'vmail'@'localhost' (using password: YES) - waiting for 1 seconds before retry
Thanks!