Postfix fail to send to relay after procmail activ

hello to all, i’m a newbie in virtualmin and i’ve installed on debian4.0 rc4 webmin and virtmin from .deb packs in GPL version; i want to make a really good server from this machine but all my hops are broken, why? after install, set up, when i activate procmail in “mailbox_command” in postfix, the server sayed:

“fatal: connect #11 to subsystem private//usr/bin/procmail : No such file or directory”
and my mails on the relay from root to root and from other alias set to root were bounced and removed; after i unactivate the proc mail from postfix
“postconf mailbox_command=”
all my emails from relay to relay worked just fine…and another think all my configs were made after the how to from “howtoforge-Debian 4.0rc4 perfect server”; if any one has a ideea how i still can make my dream come true, please, tell me!
or any how to with examples are better…

You need to install procmail.

apt-get install procmail