prøv lige at hent den med den her (ret URL) og check content type:
import java.net.*;
import java.io.*;
public class ArnesWebDownloadDebugger {
   public static void download(String fileurl, String filename) {
      try {
         URL url = new URL(fileurl);
         HttpURLConnection con = (HttpURLConnection) url.openConnection();
         con.connect();
         int status = con.getResponseCode();
         if (status == HttpURLConnection.HTTP_OK) {
            InputStream is = con.getInputStream();
            System.out.println("Content-Type header = " + con.getContentType());
            System.out.println("Content Length Header = " + con.getContentLength());
            OutputStream os = new FileOutputStream(filename);
            byte[] b = new byte[1000];
            int total = 0;
            int n;
            while ((n = is.read(b)) >= 0) {
               os.write(b, 0, n);
               total += n;
            }
            os.close();
            is.close();
            System.out.println("Actual length = " + total);
         } else {
            System.out.println("HTTP status = " + status);
         }
         con.disconnect();
      } catch (MalformedURLException e) {
         e.printStackTrace();
      } catch (FileNotFoundException e) {
         e.printStackTrace();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
   public static void main(String[] args) {
      download("
http://www.vajhoej.dk/arne/eksperten/showversion/showversion.class", "C:\\slet.class");
   }
}