object help please

Your Create function within the Button type is not returning the object it creates, so you're passing a null object when you call g.addgadget(b)

Change the create function in Button to this:

Function Create:button(x , y , width:Float , height:Float , text$)
Local t:button=New button
t.x = x
t.y = y
t.width = width
t.height = height
t.text = text

If img = Null
img=gui_type.gui_pointer.button_img
img2=gui_type.gui_pointer.button_over_img
Return t
EndIf

And you should be fine.