Unity Standard Assets Mobile First Person Controls not jumping

 //////////////////////////////////////////////////////////////
 // FirstPersonControl.js
 //
 // FirstPersonControl creates a control scheme where the camera 
 // location and controls directly map to being in the first person.
 // The left pad is used to move the character, and the
 // right pad is used to rotate the character. A quick double-tap
 // on the right joystick will make the character jump.
 //
 // If no right pad is assigned, then tilt is used for rotation
 // you double tap the left pad to jump
 //////////////////////////////////////////////////////////////
 
 #pragma strict
 
 @script RequireComponent( CharacterController )
 
 // This script must be attached to a GameObject that has a CharacterController
 var moveTouchPad : Joystick;
 var rotateTouchPad : Joystick;                        // If unassigned, tilt is used
 
 var cameraPivot : Transform;                        // The transform used for camera rotation
 
 var forwardSpeed : float = 4;
 var backwardSpeed : float = 1;
 var sidestepSpeed : float = 1;
 var jumpSpeed : float = 8;
 var inAirMultiplier : float = 0.25;                    // Limiter for ground speed while jumping
 var rotationSpeed : Vector2 = Vector2( 200, 200 );    // Camera rotation speed for each axis
 var tiltPositiveYAxis = 0.6;
 var tiltNegativeYAxis = 0.4;
 var tiltXAxisMinimum = 0.1;
 
 private var thisTransform : Transform;
 private var character : CharacterController;
 private var cameraVelocity : Vector3;
 private var velocity : Vector3;                        // Used for continuing momentum while in air
 private var canJump = true;
 
 function Start()
 {
     // Cache component lookup at startup instead of doing this every frame        
     thisTransform = GetComponent( Transform );
     character = GetComponent( CharacterController );    
 
     // Move the character to the correct start position in the level, if one exists
     var spawn = GameObject.Find( "PlayerSpawn" );
     if ( spawn )
         thisTransform.position = spawn.transform.position;
 }
 
 function OnEndGame()
 {
     // Disable joystick when the game ends    
     moveTouchPad.Disable();
     
     if ( rotateTouchPad )
         rotateTouchPad.Disable();    
 
     // Don't allow any more control changes when the game ends
     this.enabled = false;
 }
 
 function Update()
 {
     var movement = thisTransform.TransformDirection( Vector3( moveTouchPad.position.x, 0, moveTouchPad.position.y ) );
 
     // We only want horizontal movement
     movement.y = 0;
     movement.Normalize();
 
     // Apply movement from move joystick
     var absJoyPos = Vector2( Mathf.Abs( moveTouchPad.position.x ), Mathf.Abs( moveTouchPad.position.y ) );    
     if ( absJoyPos.y > absJoyPos.x )
     {
         if ( moveTouchPad.position.y > 0 )
             movement *= forwardSpeed * absJoyPos.y;
         else
             movement *= backwardSpeed * absJoyPos.y;
     }
     else
         movement *= sidestepSpeed * absJoyPos.x;        
     
     // Check for jump
     if ( character.isGrounded )
     {        
         var jump = false;
         var touchPad : Joystick;
         if ( rotateTouchPad )
             touchPad = rotateTouchPad;
         else
             touchPad = moveTouchPad;
     
         if ( !touchPad.IsFingerDown() )
             canJump = true;
         
          if ( canJump && Input.GetMouseButtonDown(0))
          {
             jump = true;
             canJump = false;
          }    
         
         if ( jump )
         {
             // Apply the current movement to launch velocity        
             velocity = character.velocity;
             velocity.y = jumpSpeed;    
         }
     }
     else
     {            
         // Apply gravity to our velocity to diminish it over time
         velocity.y += Physics.gravity.y * Time.deltaTime;
                 
         // Adjust additional movement while in-air
         movement.x *= inAirMultiplier;
         movement.z *= inAirMultiplier;
     }
         
     movement += velocity;    
     movement += Physics.gravity;
     movement *= Time.deltaTime;
     
     // Actually move the character    
     character.Move( movement );
     
     if ( character.isGrounded )
         // Remove any persistent velocity after landing    
         velocity = Vector3.zero;
     
     // Apply rotation from rotation joystick
     if ( character.isGrounded )
     {
     if(Input.GetMouseButtonDown(0))
     {
         return;
     }
         var camRotation = Vector2.zero;
         
         if ( rotateTouchPad )
             camRotation = rotateTouchPad.position;
         else
         {
             // Use tilt instead
 //            print( iPhoneInput.acceleration );
             var acceleration = Input.acceleration;
             var absTiltX = Mathf.Abs( acceleration.x );
             if ( acceleration.z < 0 && acceleration.x < 0 )
             {
                 if ( absTiltX >= tiltPositiveYAxis )
                     camRotation.y = (absTiltX - tiltPositiveYAxis) / (1 - tiltPositiveYAxis);
                 else if ( absTiltX <= tiltNegativeYAxis )
                     camRotation.y = -( tiltNegativeYAxis - absTiltX) / tiltNegativeYAxis;
             }
             
             if ( Mathf.Abs( acceleration.y ) >= tiltXAxisMinimum )
                 camRotation.x = -(acceleration.y - tiltXAxisMinimum) / (1 - tiltXAxisMinimum);
         }
         
         camRotation.x *= rotationSpeed.x;
         camRotation.y *= rotationSpeed.y;
         camRotation *= Time.deltaTime;
         
         // Rotate the character around world-y using x-axis of joystick
         thisTransform.Rotate( 0, camRotation.x, 0, Space.World );
         
         // Rotate only the camera with y-axis input
         cameraPivot.Rotate( -camRotation.y, 0, 0 );
     }
 }

So I'm using the Standard Assets (mobile) to create a Windows Phone 8 game. Specifically, the FirstPersonControl Script. My problem is with the jumping. I cannot jump. I have double-tapped the touchpad on my phone, and also set it to MouseButtonDown(0) instead. That didn't even work. I am using the Dual Joysticks. Now, if anyone could edit this script so the jumping would work, that would be amazing.