sup-tweak-labels: 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-tweak-labels - from package: sup-mail

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

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