IES light leaked trough geometry

Hey guys!
I have a trouble with IES lighting in my scene. Light leaked trough geometry. I’m render img with overrided mats, so there is no mat problem.
There is cinema hall (40x30x15m), lights are on vertical surface of stairs. Thickness of model in that place is 7mm and it’s solid.

next picture with
Power: 2
Cutoff treshold: 1

There is my settings for camera:




any thoughts?)

Your lights aren’t casting shadows, are they?

No, i dont need shadows. Only diffuse.
I’m attached scene and IES.
http://www.mediafire.com/?1bf185ro1vhp7sa

I think you do. Thats not a light leak, it’s no shadows.

Thank you, gangster!)
Now pic look like it should be, but render time increased(