ftpdctl: 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 CentOS possible default full paths are:

/usr/bin/ftpdctl - from package: proftpd

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

On Debian possible default full paths are:

/usr/bin/ftpdctl - from package: proftpd-basic

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