I\'m trying to use In-App billing:
mIabHelper = new IabHelper(this, BILLING_KEY);
mIabHelper.startSetup(new IabHelper.OnIabSetupFinishedListener() {
This error indicates that you're connecting to the in-app billing service on your device, but that the service doesn't support IAB version 3. It may be that your device's version of Google Play only supports version 2 of IAB. What version of Google Play is running on your device?
Is your version of Google Play otherwise functional (e.g., can you open the Google Play store)? Sometimes, if the date on your device is off, or there is some other problem, Google Play itself can go South.
Finally, what's in your logcat output? It would be easier to provide assistance if you provided more detail.