problems loading external model, using ncsa portfolio

I am having problems loading a .3ds model. I am using the ncsa model loader used in Killer Game Programming in Java. I think this problem is caused by the program being inside of a jar because the code works when the class files are on their own. The code that actually loads the model is here. I encountered a similar problem when loading images from within a .jar but remedied this with a solution not applicable to 3D models. Any advice on how to get this loader working would be appreciated.:

private void loadModel(String fn)
    {
      FileWriter ofw = null;
      System.out.println( "Loading: " + fn );

      try {
        ModelLoader loader = new ModelLoader();    // the NCSA portfolio loader
        // System.out.println("Loader flags: " + loader.getFlags());
        loadedScene = loader.load(fn);             // the loaded scene

        // Rotate and scale the model
        if(loadedScene != null ) {
          loadedBG = loadedScene.getSceneGroup();    // the model's BG
 
          Transform3D t3d = new Transform3D();
          t3d.rotX( -Math.PI/2.0 );    // models are often on their face; fix that
          Vector3d scaleVec = calcScaleFactor(loadedBG, fn);   // scale the model
          t3d.setScale( scaleVec );

          TransformGroup tg = new TransformGroup(t3d);
          tg.addChild(loadedBG);

          sceneBG.addChild(tg);   // add (tg->loadedBG) to scene
        }
        else
          System.out.println("Load error with: " + fn);
      }
      catch( IOException ioe )
      { System.err.println("Could not find object file: " + fn); }
    } // end of loadModel()