#! /usr/bin/perl

use strict;
use warnings;
use HTML::Template;

my $tmpl_file = '/path/to/template.tmpl';
my $template = HTML::Template->new(filename => $tmpl_file);

my %errors = (klein => 5, mittel => 10, groß => 1);

my @array;
foreach my $key(keys(%errors)){
  push(@array,{CATEGORY => $key, NUMBER => $errors{$key}});
}

$template->param(ERRORS => \@array);

my $target = '/path/to/ziel.html';

open(my $fh,">$target") or die $!;
print $fh $template->output();
close $fh;