Use the LogCat and try to find what is causing the app to crash.
To see Logcat if you use Android Studio then Press ALT + 6 or
if you use Eclipse then Window -> Open Perspective -> Other - LogCat
Go to the LogCat, from the drop down menu select error. This will contain all the required information to help you debug. If that doesn't help, post the LogCat as an edit to your question and somebody will help you out.