Cannot get pixels when webcam is not running - unity3d

Question

I get the following error when I attached coroutine TakePhoto to a button, can someone help?
Error:
Cannot get pixels when webcam is not running
UnityEngine.WebCamTexture:GetPixels ()
GetCam/d__6:MoveNext () (at Assets/GetCam.cs:52)
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)
CodeI took it from
```
using UnityEngine;
using System.Collections;
using System.IO;
using UnityEngine.UI;
public class GetCam: MonoBehaviour
{
WebCamTexture webCam;
string your_path = "C:\\Users\\Jay\\Desktop";
public RawImage display;
public AspectRatioFitter fit;
public void Start()
{
webCam = new WebCamTexture();
webCam.Play();
StartCoroutine(TakePhoto());
display.texture = webCam;
}
public void Update(){
float ratio = (float)webCam.width / (float)webCam.height;
fit.aspectRatio = ratio;
float ScaleY = webCam.videoVerticallyMirrored ? -1f: 1f;
display.rectTransform.localScale = new Vector3(1f,ScaleY, 1f);
int orient = -webCam.videoRotationAngle;
display.rectTransform.localEulerAngles = new Vector3(0,0,orient);
}
IEnumerator TakePhoto() // Start this Coroutine on some button click
{
// NOTE - you almost certainly have to do this here:
yield return new WaitForEndOfFrame();
// it's a rare case where the Unity doco is pretty clear,
// http://docs.unity3d.com/ScriptReference/WaitForEndOfFrame.html
// be sure to scroll down to the SECOND long example on that doco page
Texture2D photo = new Texture2D(webCam.width, webCam.height);
photo.SetPixels(webCam.GetPixels());
photo.Apply();
//Encode to a PNG
byte[] bytes = photo.EncodeToPNG();
//Write out the PNG. Of course you have to substitute your_path for something sensible
File.WriteAllBytes(your_path + "photo.png", bytes);
//lol
}
}