snlockf: 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 Debian possible default full paths are:

/usr/sbin/snlockf - from package: sn

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

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