Makanyane: Did you put the new preferences in the right place? A normal install of RTW will have two preferences files. One in the game directory that is now obsolete, and one in the preferences folder. It's the one in the preferences folder that you need to replace/edit.

Another problem that people might run into is that most graphics drivers allow you to force anti-aliasing from the control panel settings for your graphics card. Obviously you need to switch that off as well.