quota_nld: command not found

Have You tried accessing the binary with the full path?

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 CentOS possible default full paths are:

/usr/sbin/quota_nld - from package: quota

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/sbin/quota_nld - from package: quota

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