Java运行时中的SMCYM错误

Question

我遇到运行时错误：SMCYM 我研究了这个错误，但对我来说没有意义。这是我的代码：

   import java.applet.*;
   import java.awt.*;
import java.net.*;
import java.util.*;

public class Imagemap extends Applet {
protected Image image;      // image to display.
protected Vector rects;     // list of rectangles in it.

public void init() {
    // load the image to be displayed.
    image = this.getImage(this.getDocumentBase(), 
                  this.getParameter("image"));
    // lookup a list of rectangular areas and the URLs they map to.
    rects = new Vector();
    ImagemapRectangle r;
    int i = 0;
    while((r = getRectangleParameter("rect" + i)) != null) {
        rects.addElement(r);
        i++;
    }
}

// Called when the applet is being unloaded from the system.
// We use it here to "flush" the image. This may result in memory 
// and other resources being freed quicker than they otherwise would.
public void destroy() { image.flush(); }

// Display the image.
public void paint(Graphics g) {
    g.drawImage(image, 0, 0, this);
}

// We override this method so that it doesn't clear the background
// before calling paint().  Makes for less flickering in some situations.
public void update(Graphics g) { paint(g); }

// find the rectangle we're inside
private ImagemapRectangle findrect(int x, int y) {
    int i;
    ImagemapRectangle r = null;
    for(i = 0; i < rects.size(); i++)  {
        r = (ImagemapRectangle) rects.elementAt(i);
        if (r.inside(x, y)) break;
    }
    if (i < rects.size()) return r;
    else return null;
}

private ImagemapRectangle lastrect;

// On button down, highlight the rectangle, and display a message
public boolean mouseDown(Event e, int x, int y) {
    ImagemapRectangle r = findrect(x, y);
    if (r == null) return false;
    Graphics g = this.getGraphics();
    g.setXORMode(Color.red);
    g.drawRect(r.x, r.y, r.width, r.height);
    lastrect = r;
    this.showStatus("To: " + r.url);
    return true;
}

// On button up, unhighlight the rectangle. 
// If still inside the rectangle go to the URL
public boolean mouseUp(Event e, int x, int y) {
    if (lastrect != null) {
        Graphics g = this.getGraphics();
        g.setXORMode(Color.red);
        g.drawRect(lastrect.x, lastrect.y, lastrect.width, lastrect.height);
        this.showStatus("");
        ImagemapRectangle r = findrect(x,y);
        if ((r != null) && (r == lastrect))
            this.getAppletContext().showDocument(r.url);
        lastrect = null;
    }
    return true;
}    

我相信SMCYM错误代表：嗅到我母亲的奶酪。

请帮忙！