targen: command not found

Have You tried accessing the binary with the full path?

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/targen - from package: argyll

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