scenes that are made for the blender internal can not be guarenteed to work in yafray, lighting has to be made specificaly for yafray in most cases, and materials have to be made specificaly.  the texture should work if it is the only texture on the material, but you need to make sure the normal is facing the correct direction.  on the glass window, make sure you have fresnell mirror turned all the way up.  if you want to light that scene with only the lamp, you need to turn on global gi in the yafray gi panel.  turn it up to full, and then low.  enable photons and cache and turn the refinement down all the way.  this should do the trick of lighting the whole scene with light reflected off of the walls.