cmtk: 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/cmtk - from package: cmtk

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

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