ViewStub raises error while inflating more than one layouts conditionally

In my app, I am having a spinner, and a ViewStub, depending upon the user item selection from spinner, I have to inflate different layouts and show the inflated layout below the spinner. When my app starts, ViewStub successfully inflates a layout on first time selection of any item from spinner. When I tries to select a new item from spinner, it raises Exception below

java.lang.IllegalStateException: ViewStub must have a non-null ViewGroup viewParent

My code so far is

@Override
public void onItemSelected(AdapterView<?> pParent, View pView, int pPosition, long pId) {

if(pPosition == 1){
    m_cStub.setLayoutResource(R.layout.text_form);
}else if(pPosition == 2){
    m_cStub.setLayoutResource(R.layout.integer_form);
}
View inflated = m_cStub.inflate();
}

m_cStub is a ViewStub object created inside onCreate() of the Activity.

Here is my main layout xml code

<RelativeLayout..................>
     <spinner......................./>

     <ViewStub android:id="@+id/dynamic_form_layout"
    android:inflatedId="@+id/dynamic_form_inflated_id"
    android:layout_alignParentBottom="true"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"/>
</RelativeLayout>

Can anybody please tell me where I am going wrong. If you have any other solution to solve this please share.

Thanks.