i can't add myself as admin, when i type \rcon addadmin is says "no \rconpassword" when i set the password it says the same thing, when i host ingame server and type \Addadmin it says "unknown command" and when i type \rcon addadmin it says "rcon. \rconpassword, rcon address"
how can i fis this problem?

If your server hasn't got a mod such as OSP or ROC mod then addadmin wont work. If you have one of these mods then type the following without the quotes
set rconpassword "password here" hit enter and that will set the password for the server. Now type rcon addadmin # (# = id number). If that doesn't work then type again without the quotes rconpassword "password here" hit enter. Then rcon addadmin # and you should be fine.

also try admin mod or ztmod (ztmod is the newest version and is better in my opinion but i used admin mod for a long time before that)

these mods add lots of admin commands as well as other great features.

you may download these mods here