gupnp-av-cp: 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/gupnp-av-cp - from package: gupnp-tools

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

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