hypnotoad: 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/hypnotoad - from package: libmojolicious-perl

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

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