drbl4imp: 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/drbl4imp - from package: drbl

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

Error in other languages:
drbl4imp: bevel nie gevind nie
drbl4imp: comandă negăsită
drbl4imp: comando não encontrado
drbl4imp: commande introuvable
drbl4imp: command not found
drbl4imp: käsku ei ole
drbl4imp: không tìm thấy lệnh
drbl4imp: komanda nerasta
drbl4imp: Kommando nicht gefunden.
drbl4imp: kommandot finns inte
drbl4imp: komut yok
drbl4imp: nie znaleziono polecenia
drbl4imp: níor aimsíodh an t-ordú
drbl4imp: no se encontró la orden
drbl4imp: no s'ha trobat l'ordre
drbl4imp: opdracht niet gevonden
drbl4imp: parancs nem található
drbl4imp: perintah tidak ditemukan
drbl4imp: príkaz nenájdený
drbl4imp: příkaz nenalezen
drbl4imp: команда не найдена
drbl4imp: командата не е открита
drbl4imp: 命令找不到
drbl4imp: コマンドが見つかりません