2.-
you need to add this feature
<uses-feature android:name="android.hardware.camera" android:required="false"/>
And...
<activity android:name=".ZBarScannerActivity"
android:screenOrientation="landscape"
android:label="@string/app_name" >
<intent-filter>
<action android:name="ZBAR.SCANNER_RESULT" />
</intent-filter>
</activity>
and of course do not forget the permission inside your application
CAMERA