Plutonium

Not using set modifies an existing dvar's value
Using set declares a new dvar

Bot Warfare is a mod, so its dvars don't exist by default in the game

DookNookPanic try

exec gun.cfg map mp_downhill map mp_mirage map mp_hydro map mp_skate map mp_concert map mp_magma map mp_vertigo map mp_studio map mp_uplink map mp_bridge map mp_castaway map mp_paintball map mp_dig map mp_frostbite map mp_pod map mp_takeoff