Issue adding footer to ListView android 2.1. Source not found exception given.

Question

I am trying to add a footer to my ListView. If I create the buttons via code and add the Views I dont' have any problems. If I try use an xml file and getLayoutInflator I get a "Source not found" exception. I found a lot of similiar exceptions but none that were very helpful. Can anyone point me in the right direction?

I've pulled most of this from an example here: http://www.softwarepassion.com/android-series-custom-listview-items-and-adapters/

Here is my activity:

package nmcbride.android.androidpowercalc;

import java.util.ArrayList;

import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;

public class AndroidPowerCalc extends ListActivity {
    /** Called when the activity is first created. */

    private ProgressDialog m_ProgressDialog = null;
 private ArrayList<Calculation> m_calculations = null;
 private CalculationAdapter m_adapter;
    private Runnable viewCalculations;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        m_calculations = new ArrayList<Calculation>();
        this.m_adapter = new CalculationAdapter(this, R.layout.history_calculation_layout, m_calculations);

//        ListView lv = getListView();
//        LayoutInflater inflater = getLayoutInflater();
//        ViewGroup footer = (ViewGroup)inflater.inflate(R.layout.history_footer, lv, false);
//        lv.addHeaderView(footer, null, false);

        View history_footer = getLayoutInflater().inflate(R.layout.history_footer, getListView());
        getListView().addFooterView(history_footer);

//        addButton = new Button(this);
//        addButton.setText("Add");
//        this.getListView().addFooterView(addButton);

        setListAdapter(m_adapter);

        viewCalculations = new Runnable(){
            //@Override
            public void run() {
                getCalculations();
            }
        };

        Thread thread =  new Thread(null, viewCalculations, "MagentoBackground");
        thread.start();
        m_ProgressDialog = ProgressDialog.show(AndroidPowerCalc.this,    
              "Please wait...", "Retrieving data ...", true);

    }

    private Runnable returnRes = new Runnable() {
        //@Override
        public void run() {
            if(m_calculations != null && m_calculations.size() > 0){
                m_adapter.notifyDataSetChanged();
                for(int i=0;i<m_calculations.size();i++)
                m_adapter.add(m_calculations.get(i));
            }
            m_ProgressDialog.dismiss();
            m_adapter.notifyDataSetChanged();
        }
    };

 private void getCalculations(){
        try{
         m_calculations = new ArrayList<Calculation>();
            Calculation o1 = new Calculation();
            o1.setCalculationString("8+8*8");
            Calculation o2 = new Calculation();
            o2.setCalculationString("9+9*9");            
            m_calculations.add(o1);
            m_calculations.add(o2);
            Thread.sleep(5000);
            Log.i("ARRAY", ""+ m_calculations.size());
        } catch (Exception e) {
         Log.e("BACKGROUND_PROC", e.getMessage());
        }
          runOnUiThread(returnRes);
    }

 public String doCalc(String calcString) {
     return calcString;
    }

    private class CalculationAdapter extends ArrayAdapter<Calculation> {

     private ArrayList<Calculation> items;

     public CalculationAdapter(Context context, int textViewResourceId, ArrayList<Calculation> items) {
      super(context, textViewResourceId, items);
      this.items = items;
     }

     @Override
     public View getView(int position, View convertView, ViewGroup parent) {
      View v = convertView;
      if (v == null) {
       LayoutInflater vi = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
       v = vi.inflate(R.layout.history_calculation_layout, null);
      }
      Calculation c = items.get(position);
      if (c != null) {
          TextView tt = (TextView) v.findViewById(R.id.computation_string);
                TextView bt = (TextView) v.findViewById(R.id.result_string);
                if (tt != null) {
                    tt.setText("Computation: " + c.getCalculationString());                            }
                if(bt != null){
                    bt.setText("Result: "+ c.getCalculationString());
              }
      }
      return v;
     }
    }   
}

Thank you in andvance.