debconf-kde-helper: 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/debconf-kde-helper - from package: debconf-kde-helper

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

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