rbwtest: 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/rbwtest - from package: pvm-examples

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

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