I am trying to learn DX10 by following this tutorial. However, my shader won't compile. Below is the detailed error message.

Build started 9/10/2012 10:22:46 PM.
     1>Project "D:\code\dx\Engine\Engine\Engine.vcxproj" on node 2 (Build target(s)).
         C:\Program Files (x86)\Windows Kits\8.0\bin\x86\fxc.exe /nologo /E"main" /Fo "D:\code\dx\Engine\Debug\color.cso" /Od /Zi color.fx 
     1>FXC : error X3501: 'main': entrypoint not found

         compilation failed; no code produced
     1>Done Building Project "D:\code\dx\Engine\Engine\Engine.vcxproj" (Build target(s)) -- FAILED.

Build FAILED.

Time Elapsed 00:00:00.05

I can easily compile the downloaded code, but I want to know how to fix this error myself.

My color.fx looks like this

  ////////////////////////////////////////////////////////////////////////////////
  // Filename: color.fx
  ////////////////////////////////////////////////////////////////////////////////


  /////////////
  // GLOBALS //
  /////////////
  matrix worldMatrix;
  matrix viewMatrix;
  matrix projectionMatrix;


  //////////////
  // TYPEDEFS //
  //////////////
  struct VertexInputType
  {
      float4 position : POSITION;
      float4 color : COLOR;
  };

  struct PixelInputType
  {
      float4 position : SV_POSITION;
      float4 color : COLOR;
  };


  ////////////////////////////////////////////////////////////////////////////////
  // Vertex Shader
  ////////////////////////////////////////////////////////////////////////////////
  PixelInputType ColorVertexShader(VertexInputType input)
  {
      PixelInputType output;


     // Change the position vector to be 4 units for proper matrix calculations.
      input.position.w = 1.0f;

     // Calculate the position of the vertex against the world, view, and projection matrices.
      output.position = mul(input.position, worldMatrix);
      output.position = mul(output.position, viewMatrix);
      output.position = mul(output.position, projectionMatrix);

     // Store the input color for the pixel shader to use.
      output.color = input.color;

     return output;
  }


  ////////////////////////////////////////////////////////////////////////////////
  // Pixel Shader
  ////////////////////////////////////////////////////////////////////////////////
  float4 ColorPixelShader(PixelInputType input) : SV_Target
  {
      return input.color;
  }


  ////////////////////////////////////////////////////////////////////////////////
  // Technique
  ////////////////////////////////////////////////////////////////////////////////
  technique10 ColorTechnique
  {
      pass pass0
      {
          SetVertexShader(CompileShader(vs_4_0, ColorVertexShader()));
          SetPixelShader(CompileShader(ps_4_0, ColorPixelShader()));
          SetGeometryShader(NULL);
      }
  }