prevent user creating a duplicate node title how to prevent user creating a duplicate node title for a content type?

I already try uniqueness module (https://drupal.org/project/uniqueness) but it's only list out the duplicate content title but not return any error message when user save the new content. Any suggestion module or code? :)
You can try the Unique field module.


  This module performs additional validation when a node is created or
  updated by a user to require that a node's title, author, language,
  and CCK fields are unique within a given context.


I have not tested it yet, but it seems promising.