btdownloadgui.bittornado: 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/btdownloadgui.bittornado - from package: bittornado-gui

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