collectd-tg: 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/collectd-tg - from package: collectd-utils

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

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