packxxk: 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/packxxk - from package: rabbitsign

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

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