registerRTSPStream: 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/registerRTSPStream - from package: livemedia-utils

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

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