Software error:
Undefined subroutine &main::data_log called at my_script.pl

##</code><code>##

#!/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'});

...

##</code><code>##

#!/usr/bin/perl
#
# Logg.pm
#
#
package MyLib::Logger;

use strict;
use warnings;

use base 'Exporter';
our @EXPORT_OK = qw( data_log ); # Exported, if explicitly requested
our $VERSION = '0.01';

sub data_log {

  my ($log_file, @data) = @_;
  my $log_fh;

  # Log data  to file
  my $timestamp = '[' . localtime() . '] ';
  if ($log_file && ($log_file !~ /^STDOUT$/i)) {

    # Allow tee-ing of logfile to STDOUT and a file ('|tee -a log_file.txt')
    if ($log_file !~ /^\|/) {
      $log_file = ">>${log_file}";
     }
    open $log_fh, $log_file or warn "Can't open $log_file: $!";
    print $log_fh $timestamp, @data, "\n";
    close $log_fh;
   }
  else {
    print $timestamp, @data, "\n";
   }

  return;
 }

1; # End of Logg.pm