Getting Camera error in Zxing Barcode Application

I am trying to use Zxing Library for developing a barcode scanner.

My activity is as follows:

public class Scanner extends Activity {  

    private static final String PACKAGE = "com.test.scan";  
    private static final String SCANNER = "com.google.zxing.client.android.SCAN";  
    private static final String SCAN_FORMATS = "UPC_A,UPC_E,EAN_8,EAN_13,CODE_39,CODE_93,CODE_128";  
    private static final String SCAN_MODE = "QR_CODE_MODE";  
    public static final int REQUEST_CODE = 1;  

    @Override  
    public void onCreate(Bundle icicle) {  
        super.onCreate(icicle);  

        setContentView(R.layout.main);  

         Button ok;  
         ok = (Button) findViewById(R.id.b1);  
         ok.setOnClickListener(new View.OnClickListener() {  

             public void onClick(View v) {  

                Intent scanIntent = new Intent(SCANNER);  
                scanIntent.setPackage(PACKAGE);  
                scanIntent.addCategory(Intent.CATEGORY_DEFAULT);  
                scanIntent.putExtra("SCAN_FORMATS", SCAN_FORMATS);  
                scanIntent.putExtra("SCAN_MODE", SCAN_MODE);  
                try {  
                    startActivityForResult(scanIntent, REQUEST_CODE);  
                } catch (ActivityNotFoundException e) {  
                     // TODO: Exception handling  
                }  
            }  

        });  
     }

Also manifest file:

    <activity android:name=".Scanner"
            android:screenOrientation="landscape"   android:configChanges="orientation|keyboardHidden"
            android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
            android:windowSoftInputMode="stateAlwaysHidden">  
                 <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />  
            </intent-filter>

</activity>