When i go to another screen app crashes

When i go to from one screen to another it revert back me to same screen....
before now i run this app multiple times it works perfectly ... i have 12 screens in my app... help me with this

Use different screens wisely

If you decided to use different screens, then you should switch them correctly, else you will run out of memory after a while...      
The recommended method of switching screens in App Inventor
(Thanks Taifun)
Also see demo: multiscreen.aia