ptrepack: 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/bin/ptrepack - from package: python-tables

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

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