1) This exception is thrown repeatedly
java.io.IOException
	at sun.awt.image.GifImageDecoder.readHeader(GifImageDecoder.java:299)
	at sun.awt.image.GifImageDecoder.produceImage(GifImageDecoder.java:126)
	at sun.awt.image.InputStreamImageSource.doFetch(InputStreamImageSource.java:257)
	at sun.awt.image.ImageFetcher.fetchloop(ImageFetcher.java:217)
	at sun.awt.image.ImageFetcher.run(ImageFetcher.java:185)

2) The second constructor is reported as an ilegal start of expression and looks very wrong.

// JBuilder API Decompiler stub source generated from class file
// Oct 17, 2006
// -- implementation of methods is not available

package sun.awt.image;

// Imports
import java.lang.Object;
import sun.awt.image.ImageFetcher$1;
import sun.awt.image.ImageFetchable;
import java.lang.ThreadGroup;
import sun.awt.image.FetcherInfo;
import java.security.PrivilegedAction;
import java.lang.Thread;

class ImageFetcher extends Thread {

  // Fields
  static final int HIGH_PRIORITY = 8;
  static final int LOW_PRIORITY = 3;
  static final int ANIM_PRIORITY = 2;
  static final int TIMEOUT = 5000;

  // Constructors
  private ImageFetcher(ThreadGroup p0, int p1) { }
  ImageFetcher(ThreadGroup p0, int p1, 1 p2) { }

  // Methods
  public static void add(ImageFetchable p0) { }
  public static void remove(ImageFetchable p0) { }
  public static boolean isFetcher(Thread p0) { }
  public static boolean amFetcher() { }
  private static ImageFetchable nextImage() { }
  public void run() { }
  private void fetchloop() { }
  static void startingAnimation() { }
  private static void stoppingAnimation(Thread p0) { }

  // Inner classes
  class ImageFetcher$1 implements PrivilegedAction {

    // Fields
    private final FetcherInfo val$info;
    private final ThreadGroup val$fetcherGroup;

    // Constructors
    ImageFetcher$1(FetcherInfo p0, ThreadGroup p1) { }

    // Methods
    public Object run() { }
  }
}

3) This class extends ImageIcon and deals with the icons to display on the buttons. Nowhere in this code can an IOException be caught.
/**
 * Title:        Virtual Collaborative Working Environment Client
 * Description:  The Client Application to use the virtual environment
 * Copyright:    Copyright (c) 2006
 * @author: Rosie Wood
 * @version 1.0
 */

import java.awt.Image;
import java.awt.Toolkit;

/**
 *an ImageIcon object for display on GUI widgets
 */
public class IconPic extends ImageIcon {
    /**
     * The default Toolkit
     */
    Toolkit toolkit=Toolkit.getDefaultToolkit();
    /**
     * Image used for icon
     */
    Image myPic;

    /*
     *Constructor sets up default image icon There are no problems displaying the gifs on the buttons. Only when a label and panels are added to the main panel when the button is pressed is there a problem. No gifs are used by my code when this occurs.
     */
    /**
     * Constructor sets up default icon
     */
    public IconPic() {
        try{
            String picFile="door.gif";
            java.net.URL imageURL = MainGUI.class.getResource(picFile);
            if (imageURL != null) {
                myPic=toolkit.getImage(imageURL);
                this.setImage(myPic);}
        }catch (Exception e){System.out.println("Cant do that"+e);}}

    /**
     * accepts the name of the file to get image from as a parameter
     * sets this icons image to the image in the file
     */
    void setImage(String i){
        String picFile=i;
        java.net.URL imageURL = MainGUI.class.getResource(picFile);
        if (imageURL != null) {
            myPic=toolkit.getImage(imageURL);
            this.setImage(myPic);}}

    /**
     *returns this imageIcon
     */
    ImageIcon getIcon(){
        return this;}

    /**
     *set icon to size required using Image method getScaledInstance
     */
    void setSize(int w,int h){
        try{
            Image pic=myPic.getScaledInstance(w,h,myPic.SCALE_FAST);
            this.setImage(pic);
        }catch(NullPointerException npx){npx.printStackTrace();}
    }

}