If anyone can help it would be much appreciated. Below is a problem with a few comments. Analysing we have:
<pre>

$mailq
Mail Queue (750 requests)
--Q-ID-- --Size-- -----Q-Time----- ------------Sender/Recipient------------
JAA01371 142 Fri Oct 26 09:59 prod
(alias database unavailable)
none
JAA01162 127 Fri Oct 26 09:49 prod
(alias database unavailable)
none
HAA28981 5545 Fri Oct 26 07:37 MAILER-DAEMON
(alias database unavailable)
root

........................etc and at the end...................

LAF20326 1266 Sun Oct 21 11:22 MAILER-DAEMON
(alias database unavailable)
prod
LAE20326 1266 Sun Oct 21 11:22 MAILER-DAEMON
(alias database unavailable)
prod
LAA20171 1244 Sun Oct 21 11:07 MAILER-DAEMON
(alias database unavailable)
prod

// prod is an oracle instance

root)56: pwd
/var/mail
isgsi01(root)57: ls -la
total 28
drwxrwxrwt 3 root mail 512 Oct 16 12:21 ./
drwxrwxrwx 26 root sys 512 Aug 3 14:52 ../
drwxrwxr-x 2 root mail 512 Aug 31 11:02 :saved/
-rw-rw---- 1 adm mail 10867 Aug 16 02:30 adm

root)57:more adm
From adm Tue Jul 17 02:30:02 2001
Received: (from adm@localhost)
by *****************(8.9.3+Sun/8.9.1) id CAA29318;
Tue, 17 Jul 2001 02:30:01 +0100 (BST)
Date: Tue, 17 Jul 2001 02:30:01 +0100 (BST)
From: Admin <adm>
Message-Id: <200107170130.CAA29318@************>
To: adm, root
Content-Length: 79

Tue Jul 17 02:30:01 BST 2001
***UPDATE /etc/acct/holidays WITH NEW HOLIDAYS***

(root)90: pwd
/var/log
(root)91: tail syslog
Oct 26 09:52:42 **********sendmail[1269]: NOQUEUE: SYSERR(root): dbm map "Alias0": unsafe map file /etc/mail/aliases: No such file or directory
Oct 26 09:53:16 **********sendmail[1272]: NOQUEUE: SYSERR(aris): dbm map "Alias0": unsafe map file /etc/mail/aliases: No such file or directory
Oct 26 09:53:16 **********sendmail[1272]: NOQUEUE: SYSERR(aris): Cannot create database for alias file /etc/mail/aliases
Oct 26 09:59:19 **********sendmail[1371]: NOQUEUE: SYSERR: putoutmsg (NO-HOST): error on output channel sending "451 dbm map "Alias0": unsafe map file /etc/mail/aliases: No such file or directory": I/O error
Oct 26 09:59:19 **********sendmail[1371]: NOQUEUE: SYSERR(prod): dbm map "Alias0": unsafe map file /etc/mail/aliases: No such file or directory

---------------- I don't know if I should play around with the following dirs/files------------

(root)8: pwd
/usr/lib/mail/mailer
(root)9: cd ..
(root)10: ls -al
total 200
drwxr-xr-x 8 root mail 512 Jul 16 17:44 ./
drwxrwxrwx 45 root bin 10240 Mar 19 2001 ../
-r--r--r-- 1 root mail 83427 May 6 1999 README
drwxrwxr-x 2 root mail 512 Mar 19 2001 cf/
drwxrwxr-x 2 root mail 512 Mar 19 2001 domain/
drwxr-xr-x 2 root mail 1536 Mar 19 2001 feature/
drwxr-xr-x 3 root mail 512 Jul 16 17:44 mailer/
drwxr-xr-x 2 root mail 512 Mar 19 2001 ostype/
drwxr-xr-x 2 root mail 512 Mar 19 2001 sh/

(root)12: ls -la /usr/bin/mail
-r-x--s--x 1 bin mail 67008 Feb 14 2001 /usr/bin/mail*

(root)13wd
/home/aris

(root)14: ls -l mail2send
-rw-r--r-- 1 aris staff 21 Oct 23 11:21 mail2send

(root)35: /usr/lib/sendmail -v aris < mail2send // aris is a local user
dbm map "Alias0": unsafe map file /etc/mail/aliases: No such file or directory
aris... queued
// when I use the same with full domainname for sender like somebody@somewhere.com the mail arrives fine at its destination

(root)15:mailq
...../......
LAA20171 1244 Sun Oct 21 11:07 MAILER-DAEMON
(alias database unavailable)
prod

KAA02364 (no control file)


</pre>

Maybe the problem is in:

(root)47: ls -al /etc/mail/main.cf
-r--r--r-- 1 bin bin 27781 Mar 19 2001 /etc/mail/main.cf

Any ideas ??
Thanks alot