var currentBrickDataArr:Vector.<Vector> = new Vector.<Vector>(roomHeight, true);

for (var i:int = 0; i < roomHeight; i++ )

{

   currentBrickDataArr[i] = new Vector.<BrickData>(roomWidth, true); //здесь ошибка

   for (var j:int = 0; j < roomWidth; j++ )

   {

      currentBrickDataArr[i][j] = new BrickData(); 

   }

}