Can anyone explain this?

Hi People. I am having a major problem here. I am just trying to make a simple Space Invaders game in BMax to practice my programming. For some reason this code I have typed below is giving me an error saying:

"Unhandled Exception:Attempt to access field or method of Null Object"

The line which is highlighted is indicated by the arrow below:

Here is the code:

Graphics 800,600,0
HideMouse()


Local Player:TSpaceShip = TSpaceShip.CreateShip(0,500)
Local GameObjectList:TList = CreateList()


While Not KeyHit(KEY_ESCAPE)

	Cls 
	
	For Objects:TGameObject = EachIn GameObjectList
	
		Objects.UpdateShip()
		Objects.DrawShip()
		
	Next
	
	Flip
	
Wend







Type TGameObject

	Field X:Int
	Field y:Int
	Field Speed:Int = 5
	Field Image:TImage
	
	
	Method DrawShip()
		
		DrawImage Image,X,Y
		
	End Method
	
	Method UpdateShip() Abstract
	
End Type




Type TSpaceShip Extends TGameObject
	
	Function CreateShip:TSpaceShip(xstart:Int,ystart:Int)
	
		Local Ship:TSpaceShip = New TSpaceShip
		
		Ship.X = xstart
		Ship.Y = ystart
		Ship.Image = LoadImage("Images/ShipImage.png")
		
		ListAddLast GameObjectList,Ship <----------
		
		Return Ship
		
	End Function
	
	
	Method UpdateShip()
	
		If KeyDown(KEY_LEFT) Then X:-Speed
		If KeyDown(KEY_RIGHT) Then X:+Speed
		
		If X<0 Then X = 0
		If X> 700 Then X = 700
		
	End Method
	
End Type

I just can't seem to figure this out. I know the answer is probably looking me right in the face, but at the moment I just can't see it and it's driving me up the wall.

Thank you for any help.