effect technique validation fail

//-----------------------------------------------------------------------------
// File: PP_ColorMonochrome.fx
//
// Desc: Effect file for image post-processing sample.  This effect contains
//       a single technique with a pixel shader that converts colored image to
//       black & white by performing post-processing on a texture.
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//-----------------------------------------------------------------------------


texture g_txSrcColor;

sampler2D g_samSrcColor =
sampler_state
{
    Texture = <g_txSrcColor>;
    AddressU = Clamp;
    AddressV = Clamp;
    MinFilter = Point;
    MagFilter = Linear;
    MipFilter = Linear;
};

//-----------------------------------------------------------------------------
// Pixel Shader: PostProcessPS
// Desc: Performs post-processing effect that converts a colored image to
//       black and white.
//-----------------------------------------------------------------------------
float3 LuminanceConv = { 0.2125f, 0.7154f, 0.0721f };

float4 PostProcessPS ( float2 Tex : TEXCOORD0 ) : COLOR0
{
    return dot( (float3)tex2D( g_samSrcColor, Tex ), LuminanceConv );
}

//-----------------------------------------------------------------------------
// Technique: PostProcess
// Desc: Performs post-processing effect that converts a colored image to
//       black and white.
//-----------------------------------------------------------------------------
technique ColorMC
{
    pass p0
    {
        VertexShader = null;
        PixelShader = compile ps_2_0 PostProcessPS();
        //ZEnable = true;
    }
}