If you are getting this error then the app has either been taken offline or has not been published yet.
To put the app online do the following.
1. Open your StickyApps Account
2. Click on the Apps Tab
3. Click Edit next to the app you are getting an error for.
4. In the App details section check to see if the app is online (if it's not the button will say offline.
5. Click on the button so that it shows green for online and then click the blue re-publish button (upper right hand corner above the phone preview).