system-setup-keyboard: 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/system-setup-keyboard - from package: system-setup-keyboard

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

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