wesnoth: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/wesnoth - from package: wesnoth

You may install the required package with command yum install {package}

Error in other languages:
wesnoth: bevel nie gevind nie
wesnoth: comandă negăsită
wesnoth: comando não encontrado
wesnoth: commande introuvable
wesnoth: command not found
wesnoth: käsku ei ole
wesnoth: không tìm thấy lệnh
wesnoth: komanda nerasta
wesnoth: Kommando nicht gefunden.
wesnoth: kommandot finns inte
wesnoth: komut yok
wesnoth: nie znaleziono polecenia
wesnoth: níor aimsíodh an t-ordú
wesnoth: no se encontró la orden
wesnoth: no s'ha trobat l'ordre
wesnoth: opdracht niet gevonden
wesnoth: parancs nem található
wesnoth: perintah tidak ditemukan
wesnoth: príkaz nenájdený
wesnoth: příkaz nenalezen
wesnoth: команда не найдена
wesnoth: командата не е открита
wesnoth: 命令找不到
wesnoth: コマンドが見つかりません