datasocket+servlets

Hi i have a library called datasocket.jar when I make compiled my .java (ex javac c.java) things seems to be Ok but when i call to the servlet I have an http 404, when I compiled whitout the methods and classes of tht library but with it declarated the servlets works, what ca be that???? please I request for your help.
here is the first lines of the code...

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import natinst.msl.datasocket.*; //this is the library and I have in /home/httpd/classes/datasocket.jar, /usr/j2sdk1.4_01/jre/lib/ext/datasocket.jar
and usr/j2sdk1.4_01/lib/datasocket.jar

public class Conect1 extends HttpServlet {
  private static final String CONTENT_TYPE = "text/html";
   String vari = "0";
   String estado;
   DataSocket ds1 = new DataSocket(); //if I coment all lines that use the datasocket.jar from this line the servlets also work.
   boolean first = false;
  /**Initialize global variables*/
  public void init() throws ServletException {
  }