ctoh: 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/ctoh - from package: styx

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