qt-qconf: 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/qt-qconf - from package: qconf

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

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