ctorrent: 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 CentOS possible default full paths are:

/usr/bin/ctorrent - from package: ctorrent

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/ctorrent - from package: ctorrent

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

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