faimond-gui: 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/sbin/faimond-gui - from package: fai-server

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