drbl-check-dm: 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/share/drbl/bin/drbl-check-dm - from package: drbl

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

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