CharacterController and Animator components together damage isGrounded variable behaviour

Hi guys, how are you?

I have a big problem here! If someone could help me. I am creating a 2D platform game with Unity 4.3. I created a component which is basically a sprite (from Unity 4.3), a characterController and a Animator component.

Before I added the Animator component everything was working properly, but now, the animations are working but the variable CharacterController.isGrounded is always defined as false. Therefore, my jumps are not working.

Oh, I also notice that if i check the option Animate Physics and let the player above a platform for a while, the variable isGrounded will be true in a short period of time.

Does someone know how to fix this?

Here is a part of my code:

 // if is jumping, apply gravity. Otherwise, process vertical movement.
 if (!controller.isGrounded) {
     [...]
     if (movement.x != 0) {
          animator.Play("Running");
     }
 } else if (Input.GetButtonDown("Jump")) {
     movement.y = PlayerModel.JUMP_SPEED;
     animator.Play("Jumping");
 }