ksirk: 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/ksirk - from package: kdegames

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

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