hmm.. since I'm feeling good, I'll give you a quick lesson in why you got that error, rather then just fixing it.
The error type is "nil", this happens because the "object" you are referencing to does not exist. The "object" in this case is the window. You are referencing it by calling ".update" on "@window".
When you create variables, you also have to define them. In this case, you did not define @window . Here is what you did wrong:
You called the class, but you didn't assign it to the variable "@window"
Change that bolded line to:
@window = MyCustomWindow.new
and it should work.
The error type is "nil", this happens because the "object" you are referencing to does not exist. The "object" in this case is the window. You are referencing it by calling ".update" on "@window".
When you create variables, you also have to define them. In this case, you did not define @window . Here is what you did wrong:
class Scene_ShowWindow
def main
MyCustomWindow.new
Graphics.transition
You called the class, but you didn't assign it to the variable "@window"
Change that bolded line to:
@window = MyCustomWindow.new
and it should work.