basics Java klasse, hilfe erbeten

// Don't forget to comment out next line if the resulting class is run from the java root directory
package twaintest;

import java.io.File;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;

import uk.co.mmscomputing.device.scanner.Scanner;
import uk.co.mmscomputing.device.scanner.ScannerDevice;
import uk.co.mmscomputing.device.scanner.ScannerListener;
import uk.co.mmscomputing.device.scanner.ScannerIOException;
import uk.co.mmscomputing.device.scanner.ScannerIOMetadata;

public class twaintest implements ScannerListener{

  static twaintest app;  

  Scanner Scanner;
  boolean isFinished = false;

  public twaintest(String[] argv)throws ScannerIOException{
    Scanner=Scanner.getDevice();
    Scanner.addListener(this);    
    Scanner.acquire();
  }

  public void update(ScannerIOMetadata.Type type, ScannerIOMetadata metadata){
    if(type.equals(ScannerIOMetadata.ACQUIRED)){
      BufferedImage image=metadata.getImage();
      System.out.println("Have an image now!");
      try{
        ImageIO.write(image, "png", new File("mmsc_image.png"));
      }catch(Exception e){
        e.printStackTrace();
      }
    }else if(type.equals(ScannerIOMetadata.NEGOTIATE)){
      ScannerDevice device=metadata.getDevice();
      try{
//        device.setShowUserInterface(false);
//        device.setShowProgressBar(false);
//        device.setResolution(100);
      }catch(Exception e){
        e.printStackTrace();
      }
    }else if(type.equals(ScannerIOMetadata.STATECHANGE)){
      System.err.println(metadata.getStateStr());
      if(metadata.isFinished()){
        isFinished = true;
      }
    }else if(type.equals(ScannerIOMetadata.EXCEPTION)){
      metadata.getException().printStackTrace();
    }
  }

  public static void main(String[] argv){
    try{
      app=new twaintest(argv);                             // 2010-06-05
      while(!app.isFinished){                              // We need to keep the 'main' thread alive until 
        Thread.currentThread().sleep(200);                 // the native jtwain deamon thread has finished, otherwise
      }                                                    // the program is killed while the data source is still running
    }catch(Exception e){                                   // => crash inevitable
      e.printStackTrace();
    }
  }
}

C:\Programme\Java\jdk1.6.0\bin>java twaintest
Exception in thread "main" java.lang.NoClassDefFoundError: twaintest (wrong name
: uk/co/mmscomputing/device/twaintest/twaintest)
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:12
4)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
        at java.net.URLClassLoader.access$000(URLClassLoader.java:56)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:276)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)

C:\Programme\Java\jdk1.6.0\bin>java twaintest.class
Exception in thread "main" java.lang.NoClassDefFoundError: twaintest/class

C:\Programme\Java\jdk1.6.0\bin>