ttupdate: 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/ttupdate - from package: ctn

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

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