This is called a crash. The app crashed. If it only happens on one app, try uninstalling it and reinstalling it from Google play store. Make sure you've restarted your device, by holding power until it says restart. If that doesn't work, or the occurrence happens on multiple apps, do a factory reset, from backup and restore in settings. Make sure and backup all your data, because this will delete everything! If nothing works, the apps you are using must be unstable, which means they don't work well on your tablet.
Hope this helps!