pyro-xnsc: 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/pyro-xnsc - from package: pyro-gui

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

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