fondu: 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/fondu - from package: fondu

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