Seeing objects trough walls Blender Game Eengine

Hello everyone I have a big problem I’ll will try to explain it to you.


As you can see I see all the objects from the scene trough the walls.

I tried to double side them get rid of alpha nothing worked.

I’m exporting my textured objects from 3dsmax (.obj) and in blender everything looks just perfect until I launch the game engine.

If somebody would know the answer to this problem I would be so thankful I tried so many things and nothing helped.

Détails:

Blender 2.49
Python installed
3dsmax 2010

texture sizes till 2048 and all baked in 3dsmax

(i’m quite new to blender.)