Guide for resolving Errors?

[KvThiel]

Hello,

is there a guide to resolve errors?
I'm trying to connect an Interface dialog screen with buttons to simulation triggers. When starting the simulation I have one code line to open the Interface dialog screen:

dialog.Screen.Show = true;

but when executing the simulation, this screen doesn't appear and it gives the following error:

TypeError: $Root.Get("dialog.Screen") is null

is there a guide to resolve such sort of Errors. Or a sort instruction of how to couple such kind of GUI to a StateMachine simulation.

Kind regards,

KvThiel