ffrefboxrep: 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/bin/ffrefboxrep - from package: fawkes-plugin-refboxcomm

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

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