For Concave and convex effects

Hi all,

 To get concave and convex mirror effects i used
    Render texture and fisheye image effect in unity Pro.

Few days it worked fine. But now it is showing the error message as below ::

The Shader Hidden/FisheyeShader (UnityEngine.Shader) on effect camera_convex(Fisheye) is not supported on this platform!

This is the error message..

  guide me how to solve this error.

 Thank you in advance...