deluge-gtk: 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/deluge-gtk - from package: deluge-gtk

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

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