If you are getting this error when trying to download WhatsApp from the App Portal of your specific Phone (be it Play Store, AppWorld, Samsung Apps or ITunes) ; try the whatsapp download link for your specific phone OS
For Andriod – http://www.whatsapp.com/android/
For iPhone – http://www.whatsapp.com/appstore/
For Blackberry – http://www.whatsapp.com/appworld/
For Nokia – http://www.whatsapp.com/nokia/
For Nokia S40 – http://www.whatsapp.com/s40/
For Windows Phone – http://www.whatsapp.com/wp/
You may keep the below webpage handy
Helpful and Very nice receipts ! Great website! I will talk about ypu Guys!