Touble with Tkinter menus (code included)

[James Ash]

I'm writing a very simple and small Ptyhon/Tkinter application and I'm
having trouble getting the menus to appear correctly. Rather than a name
appearing on the menu bar, I see "()" instead.  Clicking on these "()" does
nothing (other than changing the appearance of them to indicated they've
been pressed).

I'm using Python 2.2.3 on Win2K, using a release downloaded from one
of the Cygwin mirrors.

This is most likely a simple mistake on my part, but I can't find it. I'm new
to Python and Tkinter both.

Any help appreciated!
Jim


#! /usr/bin/env python

# $Id$
#
# File: timecard.py

import string


from Tkinter import *



class App:

    def callback(self):
	print "called the callback!"

    def __init__(self, master):
	frame=Frame(master)
	master.title("Timecard, Implemented in Cygwin supplied Python!")
	master.maxsize(1000, 400)
	frame.pack()

	self.b = Button(frame, text="Clock In", width=8, command=self.callback)
	self.b.pack(side=LEFT, padx=2, pady=2)

	self.b = Button(frame, text="Clock Out", width=8, command=self.callback)
	self.b.pack(side=LEFT, padx=2, pady=2)

	self.b = Button(frame, text="Report", width=8, command=self.callback)
	self.b.pack(side=LEFT, padx=2, pady=2)

	self.menubar = Menu(master)

	self.filemenu=Menu(self.menubar)
	self.filemenu.add_command(master, label="Exit", command=self.callback)
	self.menubar.add_cascade(master, label="File", menu=self.filemenu)

	master.config(menu=self.menubar)

root = Tk()

app = App(root)
root.mainloop()