Flash not working

use Mojolicious::Lite;
use Data::Dumper;

get '/' => 'index';
get '/another-action' => 'another-template';

###############################
# Adds a new node to the tree #
###############################
post '/new' => sub {

    my $self = shift;
    my $num  = $self->param('num');

    $self->flash( error => "Parent node not found" ) if $num < 10;

# I got some problems here with Flash, so I did in an alternative way
#$self->stash->{'mojo.session'}->{flash}->{error} = "error comes here";
#app->log->info( Dumper ( $self->stash->{'mojo.session'} ) );
#app->log->info( Dumper ( $self->flash("error") ) );

    # Redirects to Tree listing page
    $self->redirect_to('/another-action');
};

app->start;


__DATA__
@@ another-template.html.ep
%= flash 'error'

@@ index.html.ep
<form action='/new' method='post'>
Type a number bigger then 10:
<input type='text' name='num' size='5'/>
<span class='error'>Erro: <%= flash 'error' %></span>
<input type='submit' value='Check'/>
</form>