request-key: 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:

/sbin/request-key - from package: keyutils

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

On Debian possible default full paths are:

/sbin/request-key - from package: keyutils

You may install the required package with command apt-get install {package}

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