I am not able to use the app after building it

MIT App Inventor Help
1

i am not able to go into other screen after screen 2 it shows a notification of runtime error

2

and that runtime error is ?

3

WhatsApp Image 2023-01-29 at 22.31.39
WhatsApp Image 2023-01-29 at 22.31.39540×1200 39 KB

4

Show us the blocks in Screen2 ?