kdialog geht nicht

kdialog --version
Qt: 4.4.2
KDE: 4.1.2 (KDE 4.1.1 (KDE 4.1 >= 20080828)) "release 52.2"
KDialog: 1.0

kdialog --msgbox "Hallo"

#!/usr/bin/env python
#-*- coding: iso-8859-1 -*-

# msgbox.py

import os
import Tkinter
from Tkconstants import *

class MyMsgBox:

    def __init__(self, title = "My Title", msg = "Some text"): 

        if os.name == "nt":
            self.appfont = "{Arial} 10 {normal}"
        elif os.name == "posix":
            self.appfont = "{suse sans} 15 {normal}"
        else:
            self.appfont = "{suse sans} 15 {normal}"

        self.mw = Tkinter.Tk()
        self.mw.title(title)
        # self.mw.iconname(iconname)
        self.mw.geometry("+350+300")
        self.mw.option_add("*font", self.appfont)
        self.label = Tkinter.Label(self.mw, text = msg)
        self.label.pack(side = "top", anchor = "w", padx = 50, pady = 10)

        self.btn_exit = Tkinter.Button(self.mw, text = "Ok", command = self.mw.destroy)
        self.btn_exit.focus()
        self.btn_exit.bind('<Return>', self.mwDestroy)

        self.btn_exit.pack(side = RIGHT, anchor = "e", padx = 20, pady = 15)
        self.mw.mainloop()

    def mwDestroy(self, a):
        self.mw.destroy()

if __name__ == "__main__":
   app = MyMsgBox("Hello", "Some text.")