drbl-user-rm: 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/drbl-user-rm - from package: drbl

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

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