Need Help Installing Guestbook

What am I doing wrong, I can't get it to run?

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Here are all my paths:
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path to perl: /usr/bin/perl

path to sendmail: /usr/sbin/sendmail

path to date command: /bin/date

path to python: /usr/bin/python

path to tcl: /usr/bin/tclsh

path to root directory: /s/dhenderson.com
path to root directory(if the one above fails):

/usr/local/plesk/apache/vhosts/dhenderson.com

path to cgi-bin: /s/dhenderson.com/cgi-bin
path to cgi-bin(if the one above fails):

/usr/local/plesk/apache/vhosts/dhenderson.com/cgi-bin

path to the httpdocs directory: /s/dhenderson.com/httpdocs
path to the httpdocs directory(if the one above fails):

/usr/local/plesk/apache/vhosts/dhenderson.com/httpdocs
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here is my guestbook.pl
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#!/usr/bin/perl
#########################################################################
# Guestbook v1.51 #
# Copyright (c)2000 Chi Kien Uong #
# URL: http://www.proxy2.de #
# #
# This Software is distributed under the GNU General Public #
# License. For more details see license.txt #
# #
# Administration: #
# http://www.host.com/cgi-bin/guestbook.pl?admin=enter #
# #
# For more stuff visit --> http://www.proxy2.de #
#########################################################################

# url of script
$cgiurl = "http://www.dhenderson.com/cgi-bin/guestbook.pl";

# administration password
$admin_pass = "123";

# base url to all guestbook files without trailing "/"
$bookurl = "http://www.dhenderson.com/book";

# base directory to all guestbook files from the server root without trailing "/"
$base_dir = "/usr/local/plesk/apache/vhosts/dhenderson.com/httpdocs/book";

# guestbook entries per page;
$entries = 20;
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here is my addentry.html
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<html>
<head>
<title>Guestbook - Add Entry</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>
<body bgcolor="#FFFFFF" link="#003399" topmargin="15">
<form method="post" action="/usr/local/plesk/apache/vhosts/dhenderson.com/httpdocs/book/guestbook.pl">

Check your addentry.html page.
The location is wrong

<form method="post" action="/usr/local/plesk/apache/vhosts/dhenderson.com/httpdocs/book/guestbook.pl">

should be:

<form method="post" action="http://www.dhenderson.com/cgi-bin/guestbook.pl">