Codeigniter 2.1.0: validation_errors() not displaying

[eluser]Unknown[/eluser]
I followed the user guide and I browsed/followed the instructions and suggestions in forums but I still don't get my expected results.

form_validation was autoloaded.
I'm using xampp 1.7.4

I tried these...

1.

controller...

Code:

function review(){
  if ($this->form_validation->run() == FALSE){
   $this->display->signup('signup_form');
  }else{
   ...
   //load success page
   ...
  }
}

view...

Code:

<?php var_dump(validation_errors()); ?>

2.

controller...

Code:

function review(){
  if ($this->form_validation->run() == FALSE){
   $data['errors'] = validation_errors();
   $this->display->signup('signup_form', $data);
  }else{
   ...
   //load success page
   ...
  }
}

view...

Code:

<?php var_dump($errors); ?>

3.

controller...

Code:

function review(){
  if ($this->form_validation->run() == FALSE){
   var_dump(validation_errors());
   //$this->display->signup('signup_form', $data);
  }else{
   ...
   //load success page
   ...
  }
}

and all resulted to..

Code:

string(0) ""

I already set the validation rules and they are working. My only problem is displaying the errors. Even form_error('fieldname') is not working.