falcon-conf: 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/falcon-conf - from package: falconpl-dev

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

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