[Maxximou5]

In console you would do:
sm_rcon hostname
The server would reply with:
"hostname" = "THIS IS SOME RANDOM HOSTNAME"

Seeing as your server stated it couldn't execute server.cfg, means that the server.cfg doesn't exist.
Make sure:
1) It is located in the /cfg folder of your game server
2) The file has the proper extension, .cfg and not .cfg.txt or some other random name

You can give us a screenshot so we can make sure.