exrstats: 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/bin/exrstats - from package: exrtools

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

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