We recently uploaded an update which broke RunDouble on many user's phones.
This was due to a change in part of the Android Development Kit (ADK), which Google supplies to developers. It meant that the app ran perfectly in our development environment, but when we pushed a version to the Android Market / Google Play, it didn't work for many users.
I'm pleased to say that we made a fixed version available within an hour, though it may take a little while to become visible to all users. To update, just go to "My Apps" in Google Play, and you should see the new version.
If you've left us negative feedback, we fully understand. These things happen, and most people will only leave feedback when they hit a bump, rather than when they are pleased. So I would urge you to update your feedback if RunDouble is now working ok for you.
As always, please feel free to contact us at email@example.com if there is anything we can do for you.