quotastats: 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 CentOS possible default full paths are:

/usr/sbin/quotastats - from package: quota

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

On Debian possible default full paths are:

/usr/sbin/quotastats - from package: quota

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

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