Nbiernate缓存配置

<hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">
<session-factory>
<property name="connection.provider">NHibernate.Connection.DriverConnectionProvider, NHibernate</property>
<property name="connection.driver_class">NHibernate.Driver.SqlClientDriver</property>
<property name="connection.connection_string">Data Source=PC-DEV01-004\;Initial Catalog=Hhibernate;User ID=sa;Password=sasa</property>
<property name="show_sql">true</property>
<property name="dialect">NHibernate.Dialect.MsSql2005Dialect</property>
<property name="proxyfactory.factory_class">NHibernate.ByteCode.LinFu.ProxyFactoryFactory, NHibernate.ByteCode.LinFu</property>
      <property name="hibernate.cache.provider_class">NHibernate.Caches.SysCache.SysCacheProvider,NHibernate.Caches.SysCache</property>
      <property name="expiration">120</property>
      <property name ="cache.use_second_level_cache">true</property>
</session-factory>
</hibernate-configuration>
编译的时候，系统提示这里有错误，配置缓存难道我写错了，请指教！