Procmail problem

Hello.

I try to use procmail and have some little problem (I'm using Ubuntu
6.10). In postfix configuration I was add:

mailbox_command = procmail -a "$EXTENSION"

Then next I see in mail.log that "Apr 17 11:37:52 my
postfix/local[1469]: 85C53364142: to=, relay=local,
delay=9.7, delays=1.6/0/0/8, dsn=2.0.0, status=sent (delivered to
command: procmail -a "$EXTENSION") " mail is delivered to procmail. My
file .procmailrc is located in /etc/ and looks:

SHELL=/bin/sh
MAILDIR=${HOME}/Maildir
LOGFILE=${MAILDIR}/procmail.log
LOG="--- Logging ${LOGFILE} for ${LOGNAME}, "
VERBOSE=yes
DEFAULT=${MAILDIR}/new

# skip procmail config files in user path
DROPPRIVS=yes

#Whatever recipes you'll use
#The order of the recipes is significant
:0
* ^From: scam@cyberspam\.com
/dev/null

# Accept all the rest to your default mailbox
:0:
${DEFAULT}

The problem is that when I will send any e-mail to test@test.com I can't
see any errors and any delivered messages.

What I'm doing wrong?

--
Thanks,
Peter