kmk_sleep: 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/kmk_sleep - from package: kBuild

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

On Debian possible default full paths are:

/usr/bin/kmk_sleep - from package: kBuild

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

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