Hi marco, Thanks for the response. This runs perfectly on Windows 2000 but this exception is being thrown on Windows XP. Here is the entity bean @Entity public class License implements Serializable { @Id @GeneratedValue private Long id; private Date date; private String key; private Date expirationDate; } What do u mean by NamedQuery? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3975142#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...