use HTML::Template();
use HTML::FillInForm();
use CGI();

my $string   = '<b><TMPL_VAR test></b>';
my $query    = new CGI;
my $template = new HTML::Template(scalarref => \$string);
my $fif      = new HTML::FillInForm;

print $fif->fill(scalarref => \$template->output(), 
                 fobject   => $query);

##</code><code>##

my $html = $template->output();
print $fif->fill(scalarref => \$html, 
                 fobject   => $query);