Hello this is my first application:

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mport javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.rms.*;
import java.util.*;
import java.io.*;

public class HelloWorld extends MIDlet implements CommandListener {
private Command exitCommand;
private TextBox tb;

// Constructor of the HelloWorld class
public HelloWorld() {
// Create "Exit" Command so the user can exit the MIDlet
exitCommand = new Command("Exit", Command.EXIT, 1);

// Create TextBox in which the output will be displayed
tb = new TextBox("Hello MIDlet", "Hello, World!", 15, 0);

// Add the Command and set the CommandListener
tb.addCommand(exitCommand);
tb.setCommandListener(this);

// Set our TextBox as the current screen
Display.getDisplay(this).setCurrent(tb);
}

// Called by the system when the MIDlet is started
// for the first time, and when it is resumed after
// being paused.
protected void startApp() {}

// Called by the system when the MIDlet is paused.
// In this application, there is no need to do anything
// when we are paused.
protected void pauseApp() {}

// Called when the MIDlet is destroyed. In this case,
// there is no need to do anything when we are destroyed.
protected void destroyApp(boolean force) {}

// This method is called automatically by the system
// in response to a user activating one of the Commands.
public void commandAction(Command c, Displayable d) {
// Upon receiving the "Exit" Command, destroy ourselves
if (c == exitCommand) {
destroyApp(false);
notifyDestroyed();
}
}
}

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My jad
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MIDlet-Name: HelloWorld
MIDlet-Version: 0.0.3
MIDlet-Vendor: Nokia
MIDlet-Jar-URL: HelloWorld.jar
MIDlet-Jar-Size: 1980
MIDlet-Description: My app
MIDlet-Icon: /icon.png
MicroEdition-Profile: MIDP-2.0
MicroEdition-Configuration: CLDC-1.0
MIDlet-1: HelloWorld, /icon.png, HelloWorld
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My MANIFEST
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MIDlet-Name: HelloWorld
MIDlet-Version: 0.0.3
MIDlet-Vendor: Nokia
MIDlet-Jar-URL: HelloWorld.jar
MIDlet-Description: My app
MIDlet-Icon: /icon.png
MicroEdition-Profile: MIDP-2.0
MicroEdition-Configuration: CLDC-1.0
MIDlet-1: HelloWorld, /icon.png, HelloWorld
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my compiler .bat
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javac -target 1.1 -d "classes/examples" -classpath classes -bootclasspath "C:\Nokia\Devices\Series_60_MIDP_Concept_SDK_Beta_0_3_1_Nokia_edition\lib\classes.zip" helloworld.java-----------------------------------------------------------
My "do jar" .bat
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jar -cvfm HelloWorld.jar MANIFEST.MF -C examples/ Helloworld.class icon.png
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then emulator return this error:

Unable to create MIDlet HelloWorld
java.lang.classNotFoundException: HelloWorld

then other windows which informed me that maybe I use a later version of 1.4.1 (it's true) and I have preverify error

Where I wrong?
thanks