Error while export screen

Hi,
I am trying to export one screen to my other project but when I try to export .ais screen name is “leader” but the error is only screen1 always export.
Then I have tried this ;

But now when I open my project, I always get below error ;
com.google.gwt.core.client.JavaScriptException: (TypeError) : Cannot read property ‘He’ of null

It may happen due to extension used in the screen. Is there any outdated extension???

No, all extension versions are same in original and copied screen project.

Remove the extension from screen and then export