open (TEMPLATE, $templatePath) || die "can't open $templatePath: $!";

my $template_tree = HTML::TreeBuilder->new();
$template_tree->parse_file (\*TEMPLATE);

my $first_comment = $template_tree->look_down("_tag", "~comment");
if (not defined $first_comment)
{
    warn "No comment found in template\n";
}

prompt>perl -w test.pl
No comment found in template
prompt>