how to get the built in validation error messages of CakePHP displayed?

Question

I am trying to use the built in validation functions of cakePHP for my registration/login page.

<?php
class User extends AppModel
{
    var $name = 'User';
    var $validate = array(
                          'name' => VALID_NOT_EMPTY,
                          'password' => VALID_NOT_EMPTY,
                          'email_id' => VALID_EMAIL
                         );
}

I do not have a separate view file for register or login. I have both the registration and login code of the application in a main controller and the views in a single index.ctp file. If the registration or login is valid, the page is redirected to the home page of the main controller.

class UsersController extends AppController 
{
    var $name = 'Users';
    var $helpers = array('Html', 'Form' );

    function register()
    {
     if (!empty($this->data))
      {
     if ($this->User->save($this->data))
     {
       $this->Session->setFlash('Your registration information was accepted.');
       $this->redirect('/main/home');
     }

   }
    }
 }

Index.ctp

<p>Please fill out the form below to register an account.</p>
<?php 
      echo $form->create('User', array('action' => 'register'));
      echo $form->input('name');
      echo $form->input('email_id');
      echo $form->input('password');
      echo $form->end('Register');
?>

<h3>Login</h3>
<?php
      echo $form->create('User',array('action'=>'login'));
      echo $form->input('email_id');
      echo $form->input('password');
      echo $form->end('Login');
?>

Is that why, the custom error messages are not displayed. Because, if I have a separate view file for register module, then I get the custom messages.

But I do not want a separate register view file and a separate login view file. I want to have both the functions in index file of the main controller. Could you help me?

EDIT 1

If I use render,this is what I get in the browser.

Your registration failed.

Not Found

Error: The requested address '/users/register' was not found on this server.

This is the register function in main controller:

function register()
 {
   if (!empty($this->data))
   {
     if ($this->User->save($this->data))
     {
       $this->Session->setFlash('Your registration information was accepted.');
       $this->render('home');
     }
     else
     {
      $this->Session->setFlash('Your registration failed.');
         $this->render('index');
     }

   }
 }

Answer 1

There might be a conflict going on because you're creating two forms that use the same model. If you comment out the login form, do the error messages show up then?