[Mailman-Users] /bin/sh: mailman: command not found

[thomas Armstrong]

Hi.

I'm trying to configure Mailman on my Linux server with Sendmail.

1) I installed it on '/usr/lib/mailman/'
2) I created a crontab (as root):
$ crontab /usr/lib/mailman/cron/crontab.in -u mailman

I'm able to subscribe a new user, but when trying to send a new message to
the mail list, I don't get any answer. There is also no message within the 
list archive.

And I'm getting this mail within my '/var/spool/mail/root': 
-----------------------------------------------------
To: mailman at foo.com
Subject: Cron <mailman at www> mailman /usr/lib/mailman/cron/gate_news
X-Cron-Env: <SHELL=/bin/sh>
X-Cron-Env: <HOME=/usr/lib/mailman>
X-Cron-Env: <PATH=/usr/bin:/bin>
X-Cron-Env: <LOGNAME=mailman>
X-Cron-Env: <USER=mailman>
 
/bin/sh: mailman: command not found
-----------------------------------------------

What am I doing wrong? Thank you very much.