error CS0101

Hello can somone help me?

error CS0101: The namespace global::' already contains a definition for ColorCorrectionEffect'

Here's the code:

         using UnityEngine;
         using System.Collections;
         
         [ExecuteInEditMode]
         
         [AddComponentMenu("Image Effects/Color Correction (Ramp)")]
         
     public class ColorCorrectionEffect : ImageEffectBase
     {
          public Texture  textureRamp;
               
          void OnRenderImage (RenderTexture source, RenderTexture destination)
          {
               material.SetTexture ("_RampTex", textureRamp);
               Graphics.Blit (source, destination, material);
          }
     }

i'm using unity 4.2.1