well, there's not much we can do about the run/walk button. my understanding is that the game has some wierd issues with that to begin with. if you're intent on getting that to work, my suggestion would be to backup your game saves and reinstall.
as for some slowdowns, this is unfortunately a bit normal with both of the Kotor games as the graphics engine isn't entirely optimized for the PC (the PC versions are really just Xbox ports). i myself have a Radeon 9700 Pro that is now very heavily overclocked, and i still have slowdowns in a number of areas. now, if you start seeing a 'slideshow' (the framerate drops below 20 fps), then its a good time to start posting further questions.
hope that helps.

See the struggle of the faithless lot as they negate their time
How low to sink to the depths of their frame of mind