levelset: 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/lib/cmtk/bin/levelset - from package: cmtk

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

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