Im creating a museum app
My app have 4 screens
In that app i show places around the museum to the turists go and you can switch languagues(portuguese,english,french)
My firts screen have 3 buttons to choose your language then it open another screen with a menu
But a cant go to that screen when i press the button of any of those 3 languages my app crashes
Part of your issue may be 
instead, use the closescreen block instead of open another… close screen returns you to Screen1 like magic!
With App Inventor 2, NEVER re-open Screen1
…like this 
There may be other issues Marcello.
Hint: There is no reason to change screens when you change your display to use a different language. It is easier to use perhaps a single screen and change the language on that screen as necessary.
This Forum post discusses Localization…what you want to do https://groups.google.com/forum/#!searchin/mitappinventortest/localization$20steve|sort:date/mitappinventortest/4ZYEpeElKMQ/kwKkiNSrAgAJ
The most convenient route is to establish a ‘dictionary’ for each language … see the link. Your issue becomes what is the most convenient way to provide language dictionaries. Rather than something elaborate, I would just provide a List of ‘translations’ for each language and set the language to point to the appropriate List, then use the List Index to populate your controls, labels etc with the proper translation. An example is here https://groups.google.com/forum/#!category-topic/mitappinventortest/0lwvBv7o3rE
Hint2: Have you done the Map Tour tutorial?
Wow! You have a lot of blocks !! 
You should take a look at tutorials on how to use “Any Component”
And regarding the problem of screen changes, you should see this on the @Taifun site:
