Adwhril sample example giving classnotfound exception

i am having my manifest file like this

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.basic.adwhrilsample"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="15" />

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<application
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
   <activity android:name=".Invoker" android:label="@string/app_name">

  <intent-filter>

    <action android:name="android.intent.action.MAIN" />

    <category android:name="android.intent.category.LAUNCHER" />

  </intent-filter>

  <meta-data android:value="my sdk key"

    android:name="ADWHIRL_KEY"/>

</activity>
</application>

and the below is my main.xml file

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" 
android:id="@+id/layout_main">

<com.adwhirl.AdWhirlLayout
    android:id="@+id/adwhirl_layout"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" />

</LinearLayout>

and my Invoker.java activity

package com.basic.adwhrilsample;

import android.app.Activity;
import android.os.Bundle;
import android.view.Gravity;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.RelativeLayout.LayoutParams;
import android.widget.TextView;

import com.adwhirl.AdWhirlLayout;
import com.adwhirl.AdWhirlLayout.AdWhirlInterface;
import com.adwhirl.AdWhirlManager;
import com.adwhirl.AdWhirlTargeting;

public class Invoker extends Activity implements AdWhirlInterface {

public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);

    AdWhirlManager.setConfigExpireTimeout(1000 * 60 * 5);

    AdWhirlTargeting.setAge(23);

    AdWhirlTargeting.setGender(AdWhirlTargeting.Gender.MALE);

    AdWhirlTargeting.setKeywords("online games gaming");

    AdWhirlTargeting.setPostalCode("94123");

    AdWhirlTargeting.setTestMode(false);

    AdWhirlLayout adWhirlLayout = (AdWhirlLayout)    
findViewById(R.id.adwhirl_layout);

    TextView textView = new TextView(this);

    RelativeLayout.LayoutParams layoutParams = new

    RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,

    LayoutParams.WRAP_CONTENT);

    int diWidth = 320;

    int diHeight = 52;

    int density = (int) getResources().getDisplayMetrics().density;

    adWhirlLayout.setAdWhirlInterface(this);

    adWhirlLayout.setMaxWidth((int) (diWidth * density));

    adWhirlLayout.setMaxHeight((int) (diHeight * density));

    layoutParams.addRule(RelativeLayout.CENTER_HORIZONTAL);

    textView.setText("Below AdWhirlLayout");

    LinearLayout layout = (LinearLayout) findViewById(R.id.layout_main);

    layout.setGravity(Gravity.CENTER_HORIZONTAL);

    layout.addView(adWhirlLayout, layoutParams);

    layout.addView(textView, layoutParams);

    layout.invalidate();

}

@Override
public void adWhirlGeneric() {

}

}

but i am getting

08-30 10:17:25.194: E/AndroidRuntime(564): java.lang.RuntimeException: Unable to     
instantiate activity   
ComponentInfo{com.basic.adwhrilsample/com.basic.adwhrilsample.Invoker}:  
java.lang.ClassNotFoundException: com.basic.adwhrilsample.Invoker in loader  
dalvik.system.PathClassLoader[/data/app/com.basic.adwhrilsample-2.apk]

Can anyone help me out in solving my issue. Or can anyone provide me a sample working example so that i could follow it

Updated logcat :

i think everything is allright just replace imported package replace this

 import android.widget.RelativeLayout.LayoutParams;

by

 import android.view.ViewGroup.LayoutParams;