JTDS et SQL server

Bonjour,j'essaie de me connecter à une base de données SQL server à partir d'un programme java en utilisant un pilote jTDS. Voici le code java:

import java.sql.*;
import java.io.*;
import java.sql.Driver;
import javax.sql.DataSource;
import javax.sql.ConnectionPoolDataSource;
import javax.sql.XADataSource;
import javax.naming.spi.ObjectFactory;
public class Testjdbc1{
public static void main (String[] args)throws Exception{
try {
Class.forName("net.sourceforge.jtds.jdbc.Driver");
}
catch(ClassNotFoundException e){
e.printStackTrace ();
}
String url="jdbc:jtds:sqlserver://localhost:1433/ABC4;appName=jTDS";
Connection con=DriverManager.getConnection(url);
Statement stmt=con.createStatement();
ResultSet rs=stmt.executeQuery("SELECT id_item,type_item,type1_item,state,path,file FROM T_ITEM");
while (rs.next()){
int id=rs.getInt("id_item");
int type=rs.getInt("type_item");
int type1=rs.getInt("type1_item");
int etat=rs.getInt("state");
String chemin=rs.getString("path");
String nom=rs.getString("file");
System.out.println("le nom du fichier est: "+ nom);
}

}
}

et le message d'erreur est le suivant:

Exception in thread "main" java.sql.SQLException: Network error IOException: Connection refused: connect
at net.sourceforge.jtds.jdbc.ConnectionJDBC2.<init>(ConnectionJDBC2.java:385)
at net.sourceforge.jtds.jdbc.ConnectionJDBC3.<init>(ConnectionJDBC3.java:50)
at net.sourceforge.jtds.jdbc.Driver.connect(Driver.java:182)
at java.sql.DriverManager.getConnection(DriverManager.java:525)
at java.sql.DriverManager.getConnection(DriverManager.java:193)
at Testjdbc1.main(Testjdbc1.java:17)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:516)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at net.sourceforge.jtds.jdbc.SharedSocket.createSocketForJDBC3(SharedSocket.java:304)
at net.sourceforge.jtds.jdbc.SharedSocket.<init>(SharedSocket.java:255)
at net.sourceforge.jtds.jdbc.ConnectionJDBC2.<init>(ConnectionJDBC2.java:310)
... 5 more

j'ai besoin d'une astuce pour resoudre ce problème. Merci d'avance

NB: il s'agit de SQL server 7.0