bbackupctl: 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/sbin/bbackupctl - from package: boxbackup-client

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

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