Thanks Ovid for your time spent clarifying this for me.

I understand the faults with my original script, and have corrected them accordingly.

Another problem I had which you could not have known about is that I defined $indx too early in the script since its path is dependent upon $Number

I now have the following script:

use strict;
use CGI ':standard';
use CGI::Carp qw(fatalsToBrowser warningsToBrowser);
use HTML::Template;



my $db="/path/edit/data.txt";
print header();


    open DB, "< $db" or die "Cannot open ($db) for reading: $!";
while (my $line = <DB>) {
chomp $line;
my ($word,$time,$Number,$Location) = split "\t",$line;
    if ($Number) {
    
    my $indx = "/path/pages/$Number/index.html";     
    open FILE1, "> $indx"  or die "Can't open $indx: $!";
    # open the HTML template
    my $template = HTML::Template->new(filename => $indx_tem);

    # fill in some parameters in the template
    $template->param(Location => $Location);
    $template->param(Number => $Number);
    $template->param(word => $word);

    # print the template to file
    $template->output(print_to => *FILE1);
        
    close FILE1;
    print "finish$Number<br>";       
    }
}
close DB;

print end_html();
[download]

This seems to function well and all my files are now brought up to date when I make a change to the template file.

Thanks once again for your help