kojira: command not found

Have You tried accessing the binary with the full path?

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/sbin/kojira - from package: koji-utils

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