sup-dump: 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/sup-dump - from package: sup-mail

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

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