Camera Controller Script for 2.5D SideScroller Error

Hi, I have a potentially very basic problem but I don't know what the error means.

I attach this script to a camera, and put the character as the target. Then it complains:

Assets/Standard Assets/Scripts/User/CameraController.cs(8,67): error CS1061: Type UnityEngine.Transform' does not contain a definition for x' and no extension method x' of type UnityEngine.Transform' could be found (are you missing a using directive or an assembly reference?)

But I have no clue what that means. My script is basic, it tells it to make the translate X of the camera the same as the character, what's so hard about that that it has to complain?

 using UnityEngine;
 using System.Collections;
 
 public class CameraController : MonoBehaviour {
     public GameObject target;
     
     void Update () {
         transform.position = new Vector3(target.transform.x, 0, 0);
     }
 }