Erro metodo save da classe SessionFactory

Exception in thread "main" org.hibernate.exception.SQLGrammarException: could not insert: [br.com.casa.classes.Cliente]

ackage br.com.casa.dao;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;

import br.com.casa.classes.Cliente;

public class ClienteDAO {
	
	private Session session;
	private SessionFactory factory;
	
	public ClienteDAO(){ 
		AnnotationConfiguration conf = new AnnotationConfiguration();
		conf.addAnnotatedClass(Cliente.class);
		factory = conf.buildSessionFactory();	
	}
	
	public void Adiciona(Cliente c){
		session = factory.openSession();
		[color=red]session.save(c);[/color]
		session.close(); 
	}

}