"marker1" setMarkerType "empty"
Syntax not guaranteed. When you want it to appear set the marker type to "objective" or whatever you want.
A word can be used only once in a mission. So if you have a variable "banana", you cannot have a unit called "banana" or the game will get confused. Never call anything by a reserved variable/name for the same reason. It may not be the problem, but don't call your marker "scud": call it "scudMarker" or something.
How do you know it doesn't work?