Problem using Tix.ComboBox

[Benny the Guard]

I am working on my first Python script with a UI. Was working with a ComboBox. Aftermaking some changes, unrelated to the Combo box, it now aborts. So my code is:

from Tix import *
from tkMessageBox import *
import sys
import shelve
 
class MyDbox (Frame):
    def __init__ (self,parent=None):
        Frame.__init__(self,parent)
        self.pack (expand=YES, fill=BOTH)
 
        projectFrame = Frame(self)
        projectFrame.pack (expand=YES, fill=X)
        Label (projectFrame,text='Project:').pack (side=LEFT)
 
        projectSelect = ComboBox(projectFrame,variable=self.ProjectNameVar,dropdown=1,editable=0)
 
        <.......>
 
if __name__ == '__main__':
   MyDbox  ().mainloop ()
 
 

and the error Active Python 2.5 gives is:

Traceback (most recent call last):
File "C:\Documents and Settings\Chris\Desktop\time\timekeeper.py", line 300, in <module>
LawTimeDbox (newdb).mainloop ()
File "C:\Documents and Settings\Chris\Desktop\time\timekeeper.py", line 202, in __init__
projectSelect = ComboBox(projectFrame,variable=self.ProjectNameVar ,dropdown=1,editable=0)
File "C:\Python25\lib\lib-tk\Tix.py", line 579, in __init__
cnf, kw)
File "C:\Python25\lib\lib-tk\Tix.py", line 307, in __init__
self.tk.call(widgetName, self._w, *extra)
TclError: invalid command name "tixComboBox"

Any ideas why this wouldhave been working but no longer does? The lines above did not change.