I haven't seen anyone point you in the direction of CGI::Application::ValidateRM yet - that's what I've been using recently and it works great!

The way I look at it, I have separate run_mode's for every "page" or step in the application. Then (following your example), when mode_001 is processed/submitted, it goes to mode_002 (instead of back to mode_001) and in mode_002's run_mode method, I use ValidateRM's check_rm method, which will take care of your error handling for you and you can tell it which run_mode to return to, if there was an error.

sub mode_001 {
    my ( $self, $errs ) = @_;

    # ...
    $template->param( $errs ) if $errs;
    $template->output;    
}

sub mode_002 {
    my ( $self, $results, $err_page );

    $self = shift;
    ( $results, $err_page ) = $self->check_rm( 'mode_001',
                                '_mode001_profile' );
    return $err_page if $err_page;

    # If you've gotten this far, all the data is ok per
    # your FormValidator object

}

sub _mode001_profile {
    return {
        'required' => [ qw( email password1 password2 ) ],
        'constraints' => {
                'email' => sub { return Email::Valid->address( shift )
+; }
            },
        'msgs' => {
            'any_errors' => 'some_errors',
            'prefix' => 'err_',
            },
    };
}
[download]

Hope that helps!

Peace,

Jason

Update: It will also prefill out the previous form with the user's data when/if it returns to a previous run_mode. So if they provided their first e-mail address, but not any other stuff, then it will represent the original form with the data that the user did specify along with those 'msgs' (i.e. err_password1, err_password2) that you can incorporate into your template to color things red or whatever.