Tile editor

Alright, I did the second option you have there, as the amount of tiles on the map are decided by the user.

SuperStrict

Graphics 640,480,0,60

Const tsx:Int=32	'width of each tile
Const tsy:Int=32	'height of each tile
Const frms:Int=15	'# of frames in the tile set
Const timg$="samples\tileset1.png"	'the tile set image
Const tnumx:Int=20	'# of tiles across on your map
Const tnumy:Int=15	'# of tiles down on your map

Local mx:Int,my:Int	'mouse x/y
Local ctile:Int	'currently selected tile

Global map:tilemap=tilemap.Create(tsx,tsy,timg$,tnumx,tnumy,frms)

SetColor(255,255,255)

While Not KeyHit(KEY_ESCAPE)	

	mx=MouseX()/tsx*tsx
	my=MouseY()/tsy*tsy

	map.Draw(tnumx,tnumy,tsx,tsy,ctile)
	
	If KeyHit(KEY_RIGHT)
		ctile:+1
	EndIf
	
	If KeyHit(KEY_LEFT)
		ctile:-1
	EndIf
	
	If ctile>frms-1 Then ctile=0
	If ctile<0 Then ctile=14
	
	DrawImage(map.tset,mx,my,ctile)
	
	Flip;Cls
	
Wend
End

Type tilemap

	Field tset:TImage,tiles:tile[,]	
	
	Method Draw(tnumx:Int,tnumy:Int,tsx:Int,tsy:Int,ctile:Int)			
	
		For Local x:Int=1 To tnumx
			For Local y:Int=1 To tnumy
				tiles[x,y].Draw(x*tsx,y*tsy)
			Next
		Next
		
		If MouseDown(MOUSE_LEFT)
			tiles[MouseX()/tsx,MouseY()/tsy].tfrm=ctile
		EndIf		
	
	End Method
	
	Function Create:tilemap(tsx:Int,tsy:Int,timg$,tnumx:Int,tnumy:Int,frms:Int)
		
		Local tm:tilemap=New tilemap
			tm.tset=LoadAnimImage(timg$,tsx,tsy,0,frms)	
			tm.tiles=New tile[tnumx,tnumy]
		Return tm			
		
		For Local x:Int=1 To tnumx
			For Local y:Int=1 To tnumy									
				tm.tiles[x,y].tfrm=0									
			Next
		Next					
		
	End Function

End Type

Type tile
	
	Field tfrm:Int	
	
	Method Draw(x:Int,y:Int)				
			
		SetColor(255,255,255)
		DrawImage(map.tset,x,y,tfrm)		
	
	End Method	
	
End Type

It says these two methods/fields lines are null though:

tiles[x,y].Draw(x*tsx,y*tsy)
and
tiles[MouseX()/tsx,MouseY()/tsy].tfrm=ctile

I am oblivious as to why this isn't working.. No matter what I do those lines are always null..