Simple call to static member function

[WhatMeWorry via Digitalmars-d-learn]

--------------- main.d ------------------------

void main(string[] argv)
{
  ResourceManager.LoadShader("VertexShader.glsl",
                             "FragmentShader.glsl", "filler", 
"sprite");


--------------- File ResourceManager.d ------------------------
class ResourceManager
{
public:
    static void LoadShader(string vShaderFile, string ShaderFile,
                           string gShaderFile, string name)
    {
        vShaderFile = "Do something";
        // etc.
    }

Keeps returning

main.d(173): Error: undefined identifier 'LoadShader' in module 
'ResourceManager'

I'm sure I'm doing something really dumb here but I've been 
dealing with this for many hours and thought someone here could 
spot the problem in seconds.

Thanks.