i have a program for read from a file .fx but don't read.
this file effect.fx

uniform extern float4x4 gWVP;

struct OutputVS
{
float4 posH : POSITION0;
};

OutputVS TransformVS(float3 posL : POSITION0)
{
// Zero out our output.
OutputVS outVS = (OutputVS)0;

// Transform to homogeneous clip space.
outVS.posH = mul(float4(posL, 1.0f), gWVP);

// Done--return the output.
return outVS;
}
}
float4 TransformPS() : COLOR
{
return float4(0.0f, 0.0f, 0.0f, 1.0f);
}

technique TransformTech
{
pass P0
{
// Specify the vertex and pixel shader associated with this pass.
vertexShader = compile vs_2_0 TransformVS();
pixelShader = compile ps_2_0 TransformPS();

// Specify the render/device states associated with this pass.
FillMode = Wireframe;
}
}

and read function

void CubeDemo::buildFX()
{
//khoi tao co tro store error
ID3DXBuffer *error=0;
D3DXCreateEffectFromFile(d3ddv,"effect.fx",0,0,D3DXSHADER_DEBUG,0,&FX,&error);
if(error)
{
MessageBox(0,"don't read this file transform ","error",0);
return;
}
//get handle
WVP=FX->GetParameterByName(0,"gWVP");
Tech=FX->GetTechniqueByName("TransformTech");

}

. when reading, this show a MessageBox(...);
i don't know what ?

if i copy from other file .fx ,this program run normal. but i write same that file and don't run. if copy it run.