.currentFrame special in some way?

Basically i have a mini map and i want to check what a mini map tile is playing at.
so i tried to trace it, thinking that the error i get was only because the tile was not yet instantiated i made the following function appear after 1 second to be safe.
[AS] function startGame(e:Event) {
trace(getChildByName(“tile1”).currentFrame);
}[/AS]

Still get the following error.

1119: Access of possibly undefined property currentFrame through a reference with static type flash.display:DisplayObject.

I placed .x (just a test value) instead of .currentFrame and i receive no error.

I guess .currentFrame checks for the MovieClips timeline during compilation?