echo pipe defeating recipe delivery

I have the following recipe to deal with HTML messages (a spam combatting 
tactic):

:0
* !? egrep -is -f /home/user/goodhtml.txt
* ^Content-(Transer-Encoding: base64|type: 
(text/html|multipart/(mixed|alternative)))
{
        :0 hwf
        SPAMMER=|formail -rzx "To:"

        :0 hwf
        SUB=|formail -zx "Subject:"

        #:0 f
        | echo "`date`: HTML message: from ($SPAMMER), subject ($SUB) filed in 
SPAM. 
$SPAMMER was added to the spammer list." >>delete.log

        #:0 f
        | echo "$SPAMMER" >>spammerlist

        :0
        $MAILDIR/SPAM
}

If I comment out the lines where the actions are echoed to delete.log and to 
spammerlist (as shown above), the message is delivered to SPAM. If I 
uncomment those lines, the log shows procmail as delivering 1 byte to SPAM. 

I've scoured the man pages and can't find anything that relates to using echo. 
Do any of you know why these lines would disrupt the intended delivery of my 
message?

Thanks!


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