1180: Call to a possibly undefined method Bitmap. But I've imported the right stuff, help?

Explanation:

Right so, I've been having this problem for a while now. I can't declare any variable without getting problems like these, so I can't get my work done.

Help would be GREATLY appreciated.

Errors:

1180: Call to a possibly undefined method Bitmap.

1180: Call to a possibly undefined method Bitmap.

Code:

package {

  import flash.display.MovieClip;

  import flash.text.TextField;

  import flash.events.MouseEvent;

  import flash.display.BitmapData

  import flash.display.DisplayObject

  public class MineAssign extends MovieClip {//class

  var mapBack= new Bitmap(Map);

  public function MineAssign(){//constructor

    addChild(mapBack);

  }

  }//end of class

}//end of package