I took a look and it’s crashing because there’s nothing in your top-level collection when the viewer asks for it. This is a known bug in the Android viewer that will be addressed in our next release.
Your screen grab doesn’t show whether your default collection is published. Try the following:
1) If the app isn’t built as a preflight app, check the box next to the default collection and click the publish button
2) If the app is built as a preflight app, click the preflight button in the top right of the content dashboard
3) Clear app data on the device for the app
4) Wait about 10 minutes, then run the app again
Neil