Unity 5 C# - MoveTowards is only moving in a single direction

EDIT: I fixed it. I changed grappleHitPoint from a transform to a vector3, then replaced grappleHitPoint.transform.position with just grappleHitPoint.

Hey everyone, first time posting here, anyway: I'm working on a script for a grappling hook in an FPS game. That isn't the important bit, however. Basically, I have the script working almost perfectly, except for one thing: It refuses to move towards the point I want it to move towards, and instead moves in a specific direction, regardless of rotation or anything.

EDIT: Ok, apparently this is only happening with the terrain. With other physics objects its fine, but if I try to grapple the terrain, it refuses to work.

Here's my script (for some reason it isn't including the stuff before start, sorry):

using UnityEngine; using System.Collections;

public class GrapplingHookLogic : MonoBehaviour { public GameObject grappleHook; public Transform grappleHitPoint; public bool grappled; public GameObject player; public float Speed = 5.0f;

 // Use this for initialization
 void Start () {

 }
 
 // Update is called once per frame
 void FixedUpdate () {
     if (Input.GetMouseButtonDown (1)) {
         RaycastHit hit2;
         Ray ray2 = Camera.main.ViewportPointToRay (new Vector3 (0.5f, 0.5f, 0f));
         if (Physics.Raycast (ray2, out hit2, 100)) {
             Instantiate (grappleHook,
                          hit2.point,
                          Quaternion.identity);
             grappleHitPoint = hit2.transform;
             grappled = true;

         }
     }
     if (Input.GetMouseButtonUp (1)) {
         grappled = false;
         grappleHitPoint = null;
     }
     if (grappled == true) {
         player.transform.position = Vector3.MoveTowards(transform.position, grappleHitPoint.transform.position, Speed * Time.deltaTime);
         
     }
 
 }

}

hit2.transform may be part of the problem, but that's the only thing that the script will allow for that definition without losing its mind and yelling at me to fix it. Does anyone have any idea how to fix whatever is causing this? Its stressing me out way more then something like game development has any right to. If you've got any idea what's going on with this, please let me know.