The brown lines on the dantooine sky can be solved by downloading the vista fix mentioned earlier in the thread, then disabling 'grass' option in the video menu. Maybe disabling grass would work without the fix, but I havent tried that. Hope this helps.
I'm facing a few issues myself, all reflective surfaces (sith armor, male twilek's lower part of the headtails, blaster rifles) appear as white. I have no idea why this is occuring..I'm running a dual core 1.66GHz, 1 gig RAM,vista 32 bit, intel 945 card (I know,I know, it isnt supported, and it isnt really meant for gaming,but it runs kotor real well except for this issue, and nwn2 and empire at war very smoothly at high settings)