谁帮我看看这是什么问题？（domino数据库连接的）在线等！

[ZHANGKAI_3]

import lotus.domino.*;
import javax.servlet.http.HttpServlet;
public class connet extends HttpServlet{
public connet() {
}
private static lotus.domino.Session session = null;

public static synchronized lotus.domino.Session newSession(){
try{
session = NotesFactory.createSession("192.168.255.215:8081","administrator","12345678");
}
catch(Exception e){
}
return session ;

}

public static void main(String arg[]){
connet connet = new connet();
lotus.domino.Session session = connet.newSession();
}
}

运行后出现
java.lang.NoClassDefFoundError: lotus/domino/cso/Session

at lotus.domino.NotesFactory.createSession(NotesFactory.java:67)

at domino.xml.connet.newSession(connet.java:17)

at domino.xml.connet.main(connet.java:39)

Exception in thread "main"

[chenyg2000]

还应该引入ncso.jar包