Error in Adding the In-app Billing Library

Question

I was doing this following these steps as mentioned in the link.

1. Copy the IInAppBillingService.aidl file to your Android project.
   (1) If you are

Answer 1

I did what @j2emanue suggested (click New/Package, add "com.android.vendor.billing"), and I also added that directories to my file system (com/android/vendor/billing) then copied the file in it. Then, clicked Refresh on the project. Build, and it succeeded.