Duplicate email messages...

Hi All,
I have procmail-3.10, and following .procmailrc:
 
PATH=$HOME/bin:/usr/bin:/usr/ucb:/usr/local/bin:.
 
MAILDIR=$HOME/mail    # Pine, this should be $HOME/mail
 
DEFAULT=/var/mail/testuser
LOGFILE=$MAILDIR/.logfile
LOCKFILE=$HOME/.lockmail
 
# weed out duplicate messages, first thing
:0 Wh: msgid.lock
| formail -D 8192 msgid.cache
 
# Anything that has not been delivered by now will go to $DEFAULT
# using LOCKFILE=$DEFAULT$LOCKEXT


It's not working, period!!
What am I doing wrong...
/s