An old problem with recent Micros**t assemblers. Try this:
mov ecx, SIZEOFpixelShaderData
coinvoke d3dDevice, ID3D11Device, CreateVertexShader, addr vertexShaderData, ecx, NULL, addr d3dVertexShader
If that doesn't work:
vertexShaderData db 68 ....
vertexShaderDataEnd db 0
...
mov ecx, vertexShaderDataEnd
sub ecx, vertexShaderData
coinvoke d3dDevice, ID3D11Device, CreateVertexShader, addr vertexShaderData, ecx, NULL, addr d3dVertexShader