resolvconf: 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:

/sbin/resolvconf - from package: resolvconf

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

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