Null object reference. when addChild(list)

1

hello
I’m searching since 4 hours the web and connot find the answer…

the code I put into my existing project is from a Adobe help site , I just dont know how to post it like you always do with the colors.
the problem ist when adding a fl.controls.list with addChild(listname) i get a null object reference my mainquestion is what property is null when the message comes ? or i dont know… the import is of course in the import section
and sorry for my bad english ah well maybe its important I’m using flashdevelop

[COLOR=#333333][FONT=Courier New]import fl.controls.List; [/FONT][/COLOR]
var aList:List = new List();
aList.addItem({label:“One”, data:1});
aList.addItem({label:“Two”, data:2});
aList.addItem({label:“Three”, data:3});
aList.addItem({label:“Four”, data:4});
aList.addItem({label:“Five”, data:5});
aList.setSize(60, 40);
aList.move(200,200);
addChild(aList);