OpenGL problem with SOME applications

Hello! I’m going to be mad about a tiresome problem with my Palit FX5900XT (of course, 2 years old…but never solved): since I’ve installed Forceware drivers, some applications don’t succeed to detect OpenGL drivers, others do but work bad (in particular I talk about Autocad, in which, under 3d working, the cursor clones itself etc.), the rest work fine instead. I must say that these problems disappear totally installing old drivers provided in bundle with the video card.
Please can you help me understand what I can do?
Thanks very much.