Using arrow keys (keyboard)

After further examination it shows that the code you presented is so buggy - it shouldn't even compile.

Try this:

package
{
          import flash.display.MovieClip;
          import flash.events.KeyboardEvent;
          import flash.events.Event;
          import flash.ui.Keyboard;
  
          public class Movement extends MovieClip
          {
                    private var ch1:Character;
                    private var vx:Number = 0;
                    private var vy:Number = 0;
  
                    public function Movement()
                    {
  
                              if (stage)
                                        init();
                              else
                                        addEventListener(Event.ADDED_TO_STAGE, init);
  
                    }
  
                    private function init(e:Event = null):void
                    {
                              removeEventListener(Event.ADDED_TO_STAGE, init);
                              ch1 = new Character();
                              stage.addEventListener(KeyboardEvent.KEY_DOWN, onKeyDown);
                              stage.addEventListener(KeyboardEvent.KEY_UP, onKeyUp);
                              addEventListener(Event.ENTER_FRAME, onEnterFrame);
                    }
  
                    private function onKeyDown(e:KeyboardEvent):void
                    {
                              switch (event.keyCode)
                              {
                                        case Keyboard.LEFT: 
                                                  vx = -5;
                                                  break;
                                        case Keyboard.RIGHT: 
                                                  vx = 5;
                                                  break;
                                        case Keyboard.UP: 
                                                  vy = -5;
                                                  break;
                                        case Keyboard.DOWN: 
                                                  vy = 5;
                                                  break;
  
                              }
                    }
  
                    private function onKeyUp(e:KeyboardEvent):void
                    {
                              switch (event.keyCode)
                              {
                                        case Keyboard.LEFT: 
                                        case Keyboard.RIGHT: 
                                                  vx = 0;
                                                  break;
                                        case Keyboard.UP: 
                                        case Keyboard.DOWN: 
                                                  vy = 0;
                                                  break;
  
                              }
                    }
  
                    private function onEnterFrame(e:Event):void
                    {
                              ch1.x += vx;
                              ch1.y += vy;
                    }
  
          }
}

Refactored conditionals to switches - they are faster.

There are no event listeners added to keyboard and enter frame in this code. Where do you add event listeners?