impack: 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/impack - from package: im

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

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