I get 'undefined.' But why?

Ok, I am working a tile based game. In my tile movieClip, I have on tile with an instance name. So when the character moves on top of the tile it will do ‘something’. But I can’t get it to work. Here is the script:

game.Tile39 = function () { };
game.Tile39.prototype.walkable = true;
game.Tile39.prototype.frame = 39;

if(_root.char.hitTest(_root.tile.Tile39)) {

      //do this here

}

I am testing a hitTest collision between the character (char) and tile 39 (Tile39, in the instance name in the movieClip tile).

I have done a trace(_root.tile.Tile39), but it gives me an ‘undefined’. Why is this?

Also, did I provide enough info so you can understand what I trying to get at?

I’m just a stupid designer, so I’m probably wrong…but shouldn’t you be tracing _root.game.Tile39, not _root.tile.Tile39?