Dont mess with your player profile in the Combat Arms folder. It is against the Nexon Terms of Service and could possibly result in a ban.
Change the setting ingame, in the video options (I dont think Lightmap is there though) , and If lag is a problem, Turn settings, and resolution down, blood = off, view empty cartridges = off , every thing low.
Also, end the xfire and msn messenger processes, along with AIM and anything else unnessacary. Don't end any necessary system processes.
What are your computer specs ?
(Nexon has changed things aswell to make it harder to change stuff in there)