The quick brown fox jumps over the lazy dog
Either thePlayer has not been set, or thePlayer does not have a PlayerMovement component attached to it.
Also, it’s better to use the Type version of GetComponent.
thePlayer.GetComponent(PlayerMovement).active = false;
The quick brown fox jumps over the lazy dog
Try this out then and report back.
Debug.Log (thePlayer);
Debug.Log (thePlayer.GetComponent (PlayerMovement));
The quick brown fox jumps over the lazy dog