Shadows from planes with alpha textur ...

Hi, why do i have the shadow of my whole plane inplace of just the texture from that plane?
I´ve tryed Software/OpenGL rendering - nothing changed.
I´ve also read that somebody solved the same issue while enabling the "force all materials...."checkbox inside the lamps settings. But that does not help i my scene.
What do i have to do?
Im on Fusion7 (free version)
I´ve tryed Software/OpenGL rendering - nothing changed.
I´ve also read that somebody solved the same issue while enabling the "force all materials...."checkbox inside the lamps settings. But that does not help i my scene.
What do i have to do?
Im on Fusion7 (free version)