This script from www.4cm.com works on Win NT 4.0sp6a and Win 2k Server without any problem, but fails on two different Red Hat Linux 7.1 machines.  One 7.1 machine is a Dell 166mhz with a 48mb of ram, the other is a Dell P3 600mhz with 384mb of ram. All machines are using php 4.0.4pl1. The red hat machines installed php at install time, server class installation, no mod_php installed (at least that's what rpm -qi mod_php said). Apache is compiled with mod_so.c

<?php
###############################################################
# Script Title: 4CM_Grabber
#         File: 4CM_Grabber.php
#  Description: This script will Grab information from a given web site
#       Author: John B. Abela
#        Email: support@4cm.com
#          Web: http://www.4cm.com/
#      Version: 2.0.5
#
#  Copyright ? 1996-2000 www.4cm.com.  All Rights Reserved.
#
#
#  www.4cm.com (4CM) offers no warranties on this script.
#  The downloader of the script is solely responsible for any
#  problems caused by the installation of the script or use
#  of the script, including possible legal action for the grabbing
#  of the data, as a result of this script!
#
#  ALL COPYRIGHT NOTICES REGARDING: www.4cm.com
#  MUST REMAIN INTACT IN THE SCRIPT AND IN THE HTML OF THE SCRIPT!  
#
#  For more info on this script, see:
#  http://www.4cm.com/
#
#  (Please be kind and sign our guestbook at:
#     http://www.4cm.com/guestbook/  and say your using
#       this script!!)
###############################################################

########################
## Mandatory Setting  ##
########################

$GrabURL = "http://www.theregister.co.uk";  //-  Complete URL Of The Page Your Grabbing From!
$GrabStart = "<!-- </td></Tr> -->";  //- HTML Code To Start Grab. Must Be A Unique Bit Of Code!
$GrabEnd = "<IMG SRC=\'/Themes/Normal/Sections.gif\' ALT=\'Sections\' BORDER=\'0\' WIDTH=\'150\' HEIGHT=\'15\'>";  //- HTML Code To End Grab. Must Be A Unique Bit Of Code!

#############################
## Do Not Edit Below Here  ##
## Do Not Edit Below Here  ##
#############################
$OpenFile = fopen("$GrabURL", "r"); //- DO NOT CHANGE
$RetrieveFile = fread($OpenFile, 200000);  //- Reduce This To Save Memory
$GrabData = eregi("$GrabStart(.*)$GrabEnd", $RetrieveFile, $DataPrint);
// $DataPrint[1] = str_replace("", "", $DataPrint[1]);   //- Un-Comment This Line for "Replace" purposes!
// $DataPrint[1] = str_replace("", "", $DataPrint[1]);   //- Un-Comment This Line for "Replace" purposes!
fclose($OpenFile); //- DO NOT CHANGE
echo $DataPrint[1]; //- DO NOT CHANGE
####################
## End of Script  ##
####################
?>

If i change the $GrabData = eregi(... line to
$GrabData = eregi("$GrabStart(.*)", ... basically taking out the $GrabEnd, the script works.  If i replace $GrabStart with $GrabEnd, the script works.

BUT, it will not work if I have both in the expression (on the Red Hat Linux 7.1 machines).

Why?