xqmstats: 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 Debian possible default full paths are:

/usr/sbin/xqmstats - from package: quota

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