Effect reflection stack error - Effects11

I am attempting to use the reflection features of the effects11 library to retrieve the argument list for a pass's vertex shader.
When I call GetInputSignatureElementDesc() I get a runtime check error, "Run-Time Check Failure #2 - Stack around the variable ParamDesc was corrupted."

Is this something other people have experienced? I'm hoping it isn't due to a memory error buried somewhere in my code.

Here is the code where I compile the effect an try to read in a parameter.



DWORD dwShaderFlags = D3DCOMPILE_ENABLE_STRICTNESS;
#if defined( DEBUG ) || defined( _DEBUG )
// Set the D3DCOMPILE_DEBUG flag to embed debug information in the shaders.
// Setting this flag improves the shader debugging experience, but still allows
// the shaders to be optimized and to run exactly the way they will run in
// the release configuration of this program.
dwShaderFlags |= D3DCOMPILE_DEBUG;
#endif

ID3DBlob* pErrorBlob;
ID3DBlob* compiled;

HRESULT hr=D3DX11CompileFromFile(file.c_str(),NULL,NULL,NULL,GetProfile(device).c_str(),dwShaderFlags,NULL,NULL,&compiled,&pErrorBlob,NULL);

if( FAILED(hr) )
{
if( pErrorBlob != NULL ){
throw runtime_error((char*)pErrorBlob->GetBufferPointer());
if( pErrorBlob ) pErrorBlob->Release();
}
else{
throw runtime_error("Failed to compile effect "+StringUtil::WstrToStr(file));
}
}

hr=D3DX11CreateEffectFromMemory(compiled->GetBufferPointer(),compiled->GetBufferSize(),NULL,device.GetDevice(),&effect);

compiled->Release();

if(FAILED(hr)){
throw runtime_error("Failed to create effect from file");
}

UINT i=0;
ID3DX11EffectTechnique* technique=effect->GetTechniqueByIndex(i++);

while(technique->IsValid()){
D3DX11_PASS_SHADER_DESC vsDesc;
technique->GetPassByIndex(0)->GetVertexShaderDesc(&vsDesc);
D3D11_SIGNATURE_PARAMETER_DESC paramDesc;
vsDesc.pShaderVariable->GetInputSignatureElementDesc(vsDesc.ShaderIndex,0,&paramDesc);
technique=effect->GetTechniqueByIndex(i++);
}


Right now I'm just trying to read the first parameter of the first pass of each technique to see if it will work. After the runtime error is triggered, I can hover my mouse over paramDesc, and it seems to have at least some of the correct data in it. I can't find any actual examples of how to do effect reflection, so I may be doing something wrong.