opusrtp: 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/opusrtp - from package: opus-tools

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

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