use strict;
use CGI;
use HTML::Template;

my $cgi = new CGI;
my $template = HTML::Template->new(
                  filename => 'error.tmpl',
                  associate => $cgi,
                  die_on_bad_params => 0
              );
                 
my $explanation = &get_explanation($cgi->param('err'));
$template->param(Explain => $explanation);
print $cgi->header(), $template->output();

sub get_explanation{
  my $err = $_[0];
  ##Get Explanation
}