pidfilehack: 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:

/sbin/pidfilehack - from package: minit

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

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