UnityEngine.Component does not contain definition for

I copied a script from Unity's site for camera pinch zoom but when I saved the script I got the following message in Unity. "UnityEngine.Component does not contain a definition for" and everything that contained the word orthographic and fieldOfView was after that

Here is the script using UnityEngine;

public class PinchZoom : MonoBehaviour { public float perspectiveZoomSpeed = 0.5f; // The rate of change of the field of view in perspective mode. public float orthoZoomSpeed = 0.5f; // The rate of change of the orthographic size in orthographic mode.

 void Update()
 {
     // If there are two touches on the device...
     if (Input.touchCount == 2)
     {
         // Store both touches.
         Touch touchZero = Input.GetTouch(0);
         Touch touchOne = Input.GetTouch(1);

         // Find the position in the previous frame of each touch.
         Vector2 touchZeroPrevPos = touchZero.position - touchZero.deltaPosition;
         Vector2 touchOnePrevPos = touchOne.position - touchOne.deltaPosition;

         // Find the magnitude of the vector (the distance) between the touches in each frame.
         float prevTouchDeltaMag = (touchZeroPrevPos - touchOnePrevPos).magnitude;
         float touchDeltaMag = (touchZero.position - touchOne.position).magnitude;

         // Find the difference in the distances between each frame.
         float deltaMagnitudeDiff = prevTouchDeltaMag - touchDeltaMag;

         // If the camera is orthographic...
         if (camera.isOrthoGraphic)
         {
             // ... change the orthographic size based on the change in distance between the touches.
             camera.orthographicSize += deltaMagnitudeDiff * orthoZoomSpeed;

             // Make sure the orthographic size never drops below zero.
             camera.orthographicSize = Mathf.Max(camera.orthographicSize, 0.1f);
         }
         else
         {
             // Otherwise change the field of view based on the change in distance between the touches.
             camera.fieldOfView += deltaMagnitudeDiff * perspectiveZoomSpeed;

             // Clamp the field of view to make sure it's between 0 and 180.
             camera.fieldOfView = Mathf.Clamp(camera.fieldOfView, 0.1f, 179.9f);
         }
     }
 }

}

Please help me