XML DOM error

import org.w3c.dom.*;
import javax.xml.parsers.*;
import java.io.*;

public class DOMCountElement{
public static void main(String[] args) {
try {
BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Enter File name: ");
String xmlFile = bf.readLine();
File file = new File(xmlFile);
if (file.exists()){
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
// Create the builder and parse the file
Document doc = factory.newDocumentBuilder().parse(xmlFile);
System.out.print("Enter element name: ");
String element = bf.readLine();
NodeList nodes = doc.getElementsByTagName(element);
System.out.println("xml Document Contains " + nodes.getLength() + " elements.");
}
else{
System.out.print("File not found!");
}
}
catch (Exception ex) {
System.out.println(ex);
}
}
}

the above program "To Count XML Element" was copied from this website (roseindia.net) but im getting a error like this... "java.io.IOException: Server returned HTTP response code: 503 for URL: http://www.w3.org/TR/html4/strict.dtd" im using eclipse IDE.. please help me with this. Thank u