pure-ftpd-control: 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/sbin/pure-ftpd-control - from package: pure-ftpd-common

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