Notice: Undefined property: stdClass::$uid in htmlmail_user_presave()

After programmatically create user I get error - "Notice: Undefined property: stdClass::$uid in htmlmail_user_presave() (line 179 of /sites/all/modules/htmlmail/htmlmail.module)."
Here is the code with which I created the user:

<?php
    $new_user = array(
        'name' => $form_state['values']['name'],
        'pass' => $form_state['values']['pass'],
        'mail' => $form_state['values']['email'],
        'status' => 1,
        'access' => REQUEST_TIME,
        'roles' => array(
          DRUPAL_AUTHENTICATED_RID => 'authenticated user',
          // Customer role ID = 5.
          5 => 'customer',
        ),
      );
      // Create user.
      if (user_save(NULL, $new_user)) {
        drupal_set_message("You have successfully register!");
      }
      else {
        drupal_set_message("Registration error!", 'error');
      }
    ?>

After that user successfully created with this error.