Ganz wichtig: Bei mir klappt es jetzt auch: Antialias not supported - RaceSimCentral Forums
You should open nk3d.ini and set : (located in cfg folder)
Then set all AA and AF settings in your ATi control panel and choose either overide application settings, or enhance
I use NVidia, and thats what i do. The results are superior to using settings within nK, and i find im able to use higher settings also, such as supersampling etc.