hi, I'm experiencing with shaders a bit and I keep getting this weird compilation error that's driving me crazy!

the following pixel shader code snippet:

            DirectionVector = normalize(f3LightPosition[i] - PixelPos);
            LightVec = PixelNormal - DirectionVector;

            // Get the light strenght factor
            LightStrFactor = float(abs((LightVec.x + LightVec.y + LightVec.z) / 3.0f));

            // TEST!!!
            LightStrFactor = 1.0f;

            // Add this light to the total light on this pixel
            LightVal += f4Light[i] * LightStrFactor;

works perfectly, but as soon as i remove the "LightStrFactor = 1.0f;" line, i.e. letting 'LightStrFactor ' value be the result of the calculation above, it fails to compile the shader.

LightStrFactor is a float LightVal & f4Light[i] are float4 All the rest are float3.

my question is, besides why it doesn't compile, is how come DX compiler cares about the value of a float? even if my values are incorrect, shouldn't it be run-time? the shader compilation code is this:

/* Compile the bitch */
if (FAILED(D3DXCompileShaderFromFile(fileName, NULL, NULL, "PS_MAIN", "ps_2_0", 0, &this->m_pCode, NULL, &this->m_constantTable)))
    GraphicException("Failed to compile pixel shader!");  // <-- gets here :(

if (FAILED(g_D3dDevice->CreatePixelShader( (DWORD*)this->m_pCode->GetBufferPointer(), &this->m_hPixelShader )))
    GraphicException("Failed to create pixel shader!");

this->m_fLoaded = true;

any help is appreciated thanks!!! :]