Select from the object, not the Seam component name.
select u.login from UsuarioEntity u where u.login=:login
I've already tried... =/
now I get this Exception
Exception during INVOKE_APPLICATION(5): javax.persistence.NoResultException: No entity found for query
...because nothing matched your criteria. You may want to read up on EJB3 a bit before trying to tackle Seam.
Thanks for your attention =] and for answering my thread
I'll study a little more from now on, thanks for the advice