cback: 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/cback - from package: cedar-backup2

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

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