Erro hibernate

que erro é esse ?

Hibernate: select FS_OLD.dw_seq.nextval from dual
2006-08-30 15:11:04,609 WARN  struts.action.RequestProcessor  -> Unhandled Exception thrown: class org.hibernate.HibernateException
2006-08-30 15:11:04,625 ERROR [localhost].[/fs].[action]  -> Servlet.service() for servlet action threw exception
org.hibernate.HibernateException: identifier of an instance of hibernate.DwFomento altered from 62850 to 62850
	at org.hibernate.event.def.DefaultFlushEntityEventListener.checkId(DefaultFlushEntityEventListener.java:51)