fallc.fal: command not found

Have You tried accessing the binary with the full path?

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/fallc.fal - from package: falconpl-dev

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