this._map._initRaphaelRoot is not a function

Hi all.

I followed examples, so I have included raphael-min.js, leaflet and rlayer.js

But, when I want to add marker to the map

var marker = new R.Marker(latLng,{'fill': '#fff', 'stroke': '#000'});

rlayer.js breaks at line 38:

this._map._initRaphaelRoot();
this._map._initRaphaelRoot is not a function

Did I missed some dependency or what?