Class Breaking gotoAndStop

I am making minesweeper.

I have a Movie Clip with linkage name 'tile' which is dynamically attached in a 2D array.

I have a class called 'tileClass' allowing me to define properties such as ._mine and ._marked rather than using dynamic variables such as instance["mine"]. I like using the class because it is a bit neater. This is for a Year 12 major projects so it also demonstrates a broader depth of knowledge.

My issue is that when I assign the 'tileClass' to the 'tile' Movie Clip in the library, I am no longer able to use the command 'gotoAndStop' on the tile movie clip. I use it to change between the sprites of the tile (eg. pressed, numbers, flagged). When the class is taken off I can change frames, if it is assigned, I can not. It has no errors, simply does not change the frame.

This is the class file (.as).

class tileClass{
     var _mine:Boolean;
     var _revealed:Boolean;
     var _marked:Boolean;
     var _surround:Number;
     var _xcor:Number;
     var _ycor:Number;
     function tileClass() {
          _mine = false;
          _revealed = false;
          _marked = false;
          _surround = 0;
     }
}

This is the place where I am trying to change frames

while(mineCount<(mines+1)) {
     randomNumber = Math.round(Math.random()* ((tilesDown * tilesAcross) - 1));
     tempX = randomNumber % tilesAcross; tempY = Math.floor(randomNumber / tilesAcross);
     if(_root["tile" + tempX + "_" + tempY]._mine == false) {
          _root["tile" + tempX + "_" + tempY].gotoAndStop(2);
          _root["tile" + tempX + "_" + tempY]._mine = true;
          trace("Mine: (" + tempX + "," + tempY + ") " + _root["tile" + tempX + "_" + tempY]); mineCount++;
     }
}

Any help is greatly appreciated, I have tried to find someone else with this issue and a solution but am so far unsuccessful.

-lokthelok