Tried in the irc but tired to wait there for responses. So the problem is:
I downloaded the script as supposed to, put it in the scripts folder and then to the config file I added it to the scripts list. After this I changed the game_mode in config file to "arena". It doesn't let me start the server this way - it just complains about the game not being implemented. When I start it in ctf mode, people are invincible and sometimes when I shoot at someone it just says "intel captured" for some reason.
So how do I get the arena gamemode on?