upnpd: 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/sbin/upnpd - from package: linux-igd

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

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