question about autoresponder from beginner

I set an autoresponder with procmail on Solaris 2.5.1.
I do receive the mail autosended by the procmail after i
send a mail to autoresponder(_at_)company(_dot_)com(_dot_) But then
I began to receive the same mail erery two miniutes.
About 16 mails I have received up till now.
Are there any mistakes i have made?Any advice will be 
appricated.

my steps:
1.add a user named user1 in /etc/passwd
user1:x:70017:30011:user1:/web/guide/user1:/bin/bash

2.copy .procmailrc to /web/guide/user1
  copy autoinfo.txt to /web/guide/user1

3.chown -R user1 /web/guide/user1

4.in /etc/user.txt ,add such line:
autoinfo(_at_)wayx(_dot_)com    user1

5.makedbm /etc/user.db /etc/user.txt


contents of .procmailrc

SHELL=/bin/bash
PATH=/bin:/usr/bin:/usr/ucb:/usr/local/bin:.:/opt/gnu/bin
MAILDIR=$HOME/MAIL      #you'd better make sure it exists
LOGFILE=$MAILDIR/from   #recommended
LOCKFILE=$HOME/.lockmail        #lockfile

:0
* !^FROM_DAEMON
* !^From.*MAILER-DAEMON
* !^From autoresponder
* !^* !^Subject:.*Re
* ^Received(_dot_)*autoresponder(_at_)company(_dot_)com
{

        :0 c
        | (formail  -r -A"Precedence: first-class";\
           cat $HOME/autoinfo.txt ) | $SENDMAIL -f
"autoresponder(_at_)company(_dot_)c
om" -oi -t

        :0
A                                                                   
        ! autoresponder(_at_)company(_dot_)com
}

:0 E
! autoresponder(_at_)company(_dot_)com