get-necessary-nfsd-no: 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/get-necessary-nfsd-no - from package: drbl

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

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