Lighting through glass

I have the following problem:

The Light wont go through the transparent material.

Secondly, the area beneath the lamp won’t get any lighter. I placed spotlight, arealights, dupliverted lights, everything to remove the too dark shadow, but nothing works.

Render in yafray using skydome gi with blender ao settings (osa etc. off)

In the Shaders panel, turn on TraShad for the table / table cloth material.

Did you turn on photon/caustic support?

Hope this helps…