herold: 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/herold - from package: herold

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