Erro na classe Initializer do Webwork

public class Initializer extends HttpServlet {
	AnnotationConfiguration cfg = new AnnotationConfiguration();
	/**
	 * Construtor da classe
	 *
	 */
	public Initializer(){
		// Classes Anotadas
		cfg.addAnnotatedClass(Aluno.class);	
        // Conexão com o banco de dados
        cfg.setProperty( "hibernate.dialect", "org.hibernate.dialect.PostgreSQLDialect" );
        cfg.setProperty( "hibernate.connection.driver_class", "org.postgresql.Driver" );
        cfg.setProperty( "hibernate.connection.url", "jdbc:postgresql:webwork" );
        cfg.setProperty( "hibernate.connection.username", "postgres" );
        cfg.setProperty( "hibernate.connection.password", "kamikaze" );
        cfg.setProperty( "hibernate.connection.autocommit", "true" );
        cfg.setProperty( "hibernate.connection.show_sql", "true");
	}
}

java.lang.NoSuchMethodError: org.hibernate.cfg.Mappings.<init>(Ljava/util/Map;Ljava/util/Map;Ljava/util/Map;Ljava/util/Map;Ljava/util/Map;Ljava/util/Map;Ljava/util/List;Ljava/util/List;Lorg/hibernate/cfg/NamingStrategy;Ljava/util/Map;Ljava/util/Map;Ljava/util/Map;)V
	at org.hibernate.cfg.ExtendedMappings.<init>(ExtendedMappings.java:42)
	at org.hibernate.cfg.AnnotationConfiguration.createExtendedMappings(AnnotationConfiguration.java:72)
	at org.hibernate.cfg.AnnotationConfiguration.addAnnotatedClass(AnnotationConfiguration.java:44)
	at br.com.sistema.system.Initializer.<init>(Initializer.java:24)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
	at java.lang.reflect.Constructor.newInstance(Unknown Source)
	at java.lang.Class.newInstance0(Unknown Source)
	at java.lang.Class.newInstance(Unknown Source)
	at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1048)
	at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:925)
	at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:3857)
	at org.apache.catalina.core.StandardContext.start(StandardContext.java:4118)
	at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1012)
	at org.apache.catalina.core.StandardHost.start(StandardHost.java:718)
	at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1012)
	at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:442)
	at org.apache.catalina.core.StandardService.start(StandardService.java:450)
	at org.apache.catalina.core.StandardServer.start(StandardServer.java:683)
	at org.apache.catalina.startup.Catalina.start(Catalina.java:537)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:271)
	at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:409)