ttselect: 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/ttselect - from package: ctn

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

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