Problem with shadow casting when assign my shader

Hi, When i assign my shader to a GameObject, it doesn't receive and doesn't cast shadows while before assigning shader,the GameObject worked properly with shadows. For example a shader like this:

 Shader "Examples/2 Alpha Blended Textures" {
     Properties {
         _MainTex ("Base (RGB)", 2D) = "white" {}
         _BlendTex ("Alpha Blended (RGBA) ", 2D) = "white" {}
     }
     SubShader {
         Pass {
             // Apply base texture
             SetTexture [_MainTex] {
                 combine texture
             }
             // Blend in the alpha texture using the lerp operator
             SetTexture [_BlendTex] {
                 combine texture lerp (texture) previous
             }
         }
     }
 }

How do I correct it? Thanks