"t_shooter_weapons.c" should be located inside the "include" folder in your gamestudio installation folder. If it isn't your gamestudio installation is most likely damaged.
If you located the file somewhere else you have to give the relative file name in your script, e.g.
#include "myfiles\\t_shooter_weapons.c"
Although this will work I don't recommend copying game studio files around your harddisk. Once you change one of those files or upgrade your game studio version you will get inconsistent versions. The safest way is to keep them in the "include" folder and not touching them.
