replay_driver: 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/lib/srtp/bin/replay_driver - from package: srtp-utils

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

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