iTween Question (New to coding)

So I am following this tutorial and I ran into the compile error of this:

NullReferenceException: Object reference not set to an instance of an object
iTween.CleanArgs (System.Collections.Hashtable args) (at Assets/Plugins/Pixelplacement/iTween/iTween.cs:6458)
iTween.MoveTo (UnityEngine.GameObject target, System.Collections.Hashtable args) (at Assets/Plugins/Pixelplacement/iTween/iTween.cs:1276)
ParticleFollow.Start () (at Assets/ParticleFollow.cs:11)

I know it is telling me there is something wrong with it trying to actually move it to the reference but I am not exactly sure what. My script for the particle movement is this:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ParticleFollow : MonoBehaviour {

    public string pathName;
    public float time;

	void Start () {
        iTween.MoveTo ( gameObject, iTween.Hash("path", iTweenPath.GetPath (pathName), "easetype", iTween.EaseType.easeInOutSine, "time", time) );	
	}
	
}

And the chunk of code it is wanting me to fix is this:

			if(item.Value.GetType() == typeof(System.Int32)){

Could anyone offer me some advice on how to fix this? Or at least point me in the right direction? I am really really new to unity and C# so it’s a bit overwhelming when knowing what to look for.

So I managed to get it working by looking at this fellow’s video here.

Looks to me it wanted the update code put back in. To say I know exactly what was wrong is not the case but it looks like after adding a private void Update() to the end it fixed it or at least got it working.