java.lang.SecurityException: No active admin owned by uid 10031 for policy #3

[amtandroid]

Sir please help me to solve eroor

============================================================================
on keyStatus.java
============================================================================

DevicePolicyManager dpm;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
dpm = (DevicePolicyManager)
getSystemService(Context.DEVICE_POLICY_SERVICE);
dpm.lockNow();

}






============================================================================
AndroidManifest.xml
============================================================================



<uses-permission
android:name="android.permission.USES_POLICY_FORCE_LOCK"></uses-
permission>



==============================================================================

LOG CAT

=============================================================================


02-07 16:35:47.007: ERROR/AndroidRuntime(942):
java.lang.RuntimeException: Unable to start activity
ComponentInfo{com.keyStatus/com.keyStatus.keyStatus}:
java.lang.SecurityException: No active admin owned by uid 10031 for
policy #3