Why is the crowd not appearing in my render?

To be able to get good performances Golaem Crowd characters are not real Maya geometry. They are rendered thanks to procedural plugins for your renderers, called by proxys/standins. These plugins are loading a Golaem Crowd simulation cache and handling the geometry to your renderer.

To check if everything in your scene is correctly setup for the procedural rendering to work, you should check your render settings.

Go to the CrowdRender menu (in the Rendering menu mode), and select "Check Render Settings". 
If one of these lines show a "NO", you should first correct the associated setting before trying to render.