sfconf: 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 Debian possible default full paths are:

/usr/bin/sfconf - from package: sendfile

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

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