NullPointerException beim Aufruf einer (leeren) Binder-Methode in einer Button.onClick Methode

public void onClickVerbinden(final View view){
final EditText ipAdressEingabe = (EditText) findViewById(R.id.ipAdressEingabe);
String text = ipAdressEingabe.getText().toString();
if (text.length() == 0){
isNoIp();
}
else if (isIp(text)){


final Intent networkServiceIntent = new Intent(this, NetworkService.class);
bindService(networkServiceIntent, mNetworkServiceConnection, Context.BIND_AUTO_CREATE);


//hier kommt die Exception
mNetworkServiceBinder.ConnectToServer(text);
//


unbindService(mNetworkServiceConnection);


   final Intent controlPageIntent = new Intent(this, ControlPage.class);
   startActivity(controlPageIntent);
}
else isNoIp();
}

public class NetworkService extends Service {


public class NetworkServiceBinder extends Binder {
public void ConnectToServer(String Ip) {}
public void SendCommand(String command) {}
}


private final NetworkServiceBinder mNetworkServiceBinder = new NetworkServiceBinder();


@Override
public void onCreate(){
super.onCreate();
}
@Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return mNetworkServiceBinder;
}


}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:orientation="vertical"
	android:layout_width="fill_parent"
	android:layout_height="fill_parent"
	>
	<TextView
		android:layout_width="fill_parent"
		android:layout_height="wrap_content"
		android:textSize="@dimen/standard_text"
		android:text="@string/einleitung"
	/>
	<EditText
		android:id="@+id/ipAdressEingabe"
		android:layout_width="fill_parent"
		android:layout_height="wrap_content"
	/>
	<Button
		android:layout_width="fill_parent"
		android:layout_height="wrap_content"
		android:text="@string/verbinden"
		android:onClick="onClickVerbinden"
	/>
	<TextView  
		android:layout_width="fill_parent"
		android:layout_height="wrap_content"
		android:textSize="@dimen/standard_text"
		android:text="@string/server_downloaden"
	/>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  	package="de.toolcreator.WindowsRemoteControl"
  	android:versionCode="1"
  	android:versionName="1.0">
	<uses-sdk android:minSdkVersion="8" />
	
	<uses-permission android:name="android.permission.INTERNET" /> 
  	<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
	
	<application android:icon="@drawable/wrc_icon" android:label="@string/app_name">
    	<activity android:name=".Startseite"
              	android:label="@string/app_name">
        	<intent-filter>
            	<action android:name="android.intent.action.MAIN" />
            	<category android:name="android.intent.category.LAUNCHER" />
        	</intent-filter>
    	</activity>
    	<activity
    		android:name=".ControlPage"
    		android:label="@string/ControlPage">
    	</activity>
    	<service android:name=".NetworkService" />
	</application>
</manifest>

package de.toolcreator.WindowsRemoteControl;


import android.app.Activity;
import android.app.AlertDialog;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.view.View;
import android.widget.EditText;
import de.toolcreator.WindowsRemoteControl.ControlPage;


public class Startseite extends Activity {
	
	private NetworkService.NetworkServiceBinder mNetworkServiceBinder;
	private ServiceConnection mNetworkServiceConnection =
		new ServiceConnection() {
		public void onServiceConnected(ComponentName className, IBinder binder){
			mNetworkServiceBinder = (NetworkService.NetworkServiceBinder) binder;
		}
		public void onServiceDisconnected(ComponentName className){}
	};
	
	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
    	super.onCreate(savedInstanceState);
    	setContentView(R.layout.main);
    	final Intent networkServiceIntent = new Intent(this, NetworkService.class);
		bindService(networkServiceIntent, mNetworkServiceConnection, Context.BIND_AUTO_CREATE);
	}
	
	@Override
	public void onResume(){
		super.onResume();
		final Intent networkServiceIntent = new Intent(this, NetworkService.class);
		bindService(networkServiceIntent, mNetworkServiceConnection, Context.BIND_AUTO_CREATE);
	}
	
	@Override 
	public void onPause(){
		super.onPause();
		unbindService(mNetworkServiceConnection);
	}
	
	private boolean isIp(String str){
		int anzPunkte = 0;
		char[] charStr = str.toCharArray();
		for(int i = 0; i < str.length(); i++){
			if( charStr[i] == '.')
				anzPunkte++;
		}
		if(anzPunkte == 3){
			String[] strParts = str.split("\\.");
			for(int i = 0; i < 4; i++){
				try{
					if (!((Integer.parseInt(strParts[i]) < 255)))
							return false;
				}
				catch(Exception e){
					return false;
				}
			}
			return true;
		}
		else{
			return false;
		}
		
	}
	
	private void isNoIp(){
		AlertDialog noIpAlert = new AlertDialog.Builder(this).create();
		noIpAlert.setTitle("keine IP");
		noIpAlert.setMessage("Bitte tragen Sie eine IP-Adresse in das entsprechende Feld ein.");
		noIpAlert.show();
	}
	
	public void onClickVerbinden(final View view){
		final EditText ipAdressEingabe = (EditText) findViewById(R.id.ipAdressEingabe);
		String text = ipAdressEingabe.getText().toString();
		if (text.length() == 0){
			isNoIp();
		}
		else if (isIp(text)){
			mNetworkServiceBinder.ConnectToServer(text);
			
   			final Intent controlPageIntent = new Intent(this, ControlPage.class);
   			startActivity(controlPageIntent);
		}
		else isNoIp();
	}
}