I'm lighting a simple scene -  a dark room with two spots, one on a sci-fi chamber and the other shining through a screened vent into the room.  I preview I get nice pattern on the wall from the light through the screen, but when i render the scene the pattern disappears.  I know I'm missing something here, but I can't figure it out.

 

PoserPro 2012, i7 PC with 24 gigs of ram.

The preview - which looks the way I want it - glass more transparent and the shadows on the wall and the render with no shadows and less transparent glass.