fp-registrar-email: 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/fp-registrar-email - from package: flashproxy-facilitator

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