bwctld: 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/sbin/bwctld - from package: bwctl-server

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