Validation on registration page not working

For some reason, the "request" validation is not working on the user registration page.

I have the "request" validation working on the login block and I can get the "email" validation working on the registration page.

Here is my current code:

function msnet_menu() {
  $items = array();
  
  $items[] = array(
    'path' => 'validate/user/' . arg(2),
    'title' => t(''),
    'callback' => 'msnet_validate_user',
    'callback arguments' => array(arg(2)),
    'access' => TRUE,
  );
  
  $items[] = array(
    'path' => 'validate/register/user/' . arg(2),
    'title' => t(''),
    'callback' => 'msnet_validate_register_user',
    'callback arguments' => array(arg(2)),
    'access' => TRUE,
  );
  
  return $items;
}

function msnet_form_alter($form_id, &$form) {
  if ($form_id == 'user_login' || $form_id == 'user_login_block') {
    $form['name']['#attributes']['class'] = 'request';
    $form['name']['#attributes']['validator-path'] = 'validate/user';
  } elseif ($form_id == 'user_register') {
    $form['account']['name']['#attributes']['class'] = 'request';
    $form['account']['name']['#attributes']['validator-path'] = 'validate/register/user';
    $form['account']['mail']['#attributes']['class'] = 'email';
  }
}

function msnet_validate_user($username) {
  $output = array();
  $username = check_plain($username);
  
  if ($user = user_load(array('name' => $username))) {
    $output['valid'] = TRUE;
  } else {
    $output['valid'] = FALSE;
    $output['message'] = t('Sorry, the user <strong>!username</strong> was not found.', array('!username' => $username));
  }
  
  echo json_encode($output);
  exit;
}

function msnet_validate_register_user($username) {
  $output = array();
  $username = check_plain($username);

  if ($user = user_load(array('name' => $username))) {
    $output['valid'] = FALSE;
    $output['message'] = t('Sorry, that username is already taken. Please try another usernmae.');
  } else {
    $output['valid'] = TRUE;
  }
  
  echo json_encode($output);
  exit;
}

So what am I missing?