A “Missing Layout” error means you're trying to view a page that doesn't have any content. If you've linked to a page with no content using a hotspot or a master page, here's what you'll see when previewing your app.
This is pretty easy to fix - just add content to that page, and make sure your links work correctly. Here's how to do it.
1. Go to your project build tab after logging in to App Press Now.
2. Review the hotspot and the page that is causing you to receive the error. If the hotspot says it is set to “null” in the action panel, set it to the correct page.
3. Visit the page linked from the hotspot you just fixed.
4. Add content to that page.
5. Preview your app again in App Press Now, and make sure the "Missing Layout" error has been fixed.