#!/usr/bin/perl

use strict;
use warnings;
use CGI qw(-oldstyle_urls :standard);
use Time::Zone;
use Date::Format;
use Date::Parse;
use CGI::Carp qw(fatalsToBrowser);
use CGI qw(escapeHTML);
use File::Basename;
use Data::Dumper;
use Digest::MD5 'md5_hex';
use Date::Calc qw( Today Today_and_Now Date_to_Days Add_Delta_Days );
use CGI::Session ( '-ip_match' );
use POSIX;
use JSON;
use HTML::Template;
use lib '../MyLib'; # Add private library to path  
use Logger qw(data_log); # Load source at runtime

my $q = new CGI;

$| = 1;

BEGIN
 {
  # Set log file
  my $log = 'log.log';
  use CGI::Carp qw(carpout);
  # Send all warnings to the log_file
  open STDERR, '>>', $log;
 }

# Load Main Template
my $main_templ = HTML::Template->new(filename => '../../temp/main.tmpl');

$ENV{'TZ'} = 'America/New_York';

#Logging to a file
data_log('logger_error.txt', $ENV{'TZ'});

...