In some cases, an app on an iPad may fail to launch.  This is pretty easy to resolve.  Just delete the app, and it will eventually repopulate.  press and hold on the app. The apps will start shaking.  tap the X on the corner of the app, then press the home button.  If you need the app repopulated in a hurry, you can open the app with the red flag called FileWave, and request it.  This resolves the issue.