vprerex: 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/bin/vprerex - from package: vprerex

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