kde-systemsettings-tree.py: 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/kde-systemsettings-tree.py - from package: kdesdk-scripts

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

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