Pmw Error: "TclError: can't unset "unknown_pending(": no such variable"

[Marc]

Greetings,

I'm getting an error that I can't find an explanation for. It's very
intermittent and works 99% of the time. Then that 1% comes along and
causes my app to crash. It causes a window's exception, and an error
log is generated. This is unusual because usually Python errors are
caught before it ever hits windows. Here's the error:

----------------------------------------------------------
Exception in thread Thread-1:
Traceback (most recent call last):
  File "threading.pyc", line 408, in __bootstrap
  File "threading.pyc", line 396, in run
  File "<string>", line 514, in workerThread1
  File "<string>", line 728, in provisionBits
  File "<string>", line 524, in printBitLog
  File "<string>", line 333, in PrintBitLog
  File "Pmw.pyc", line 725, in configure
  File "Tkinter.pyc", line 1093, in configure
TclError: can't unset "unknown_pending(": no such variable
----------------------------------------------------------

This is the code it hits directly before the error:
    def PrintBitLog(self, msg, line):
        self.bitsDisplay.configure(text_state=NORMAL)
        self.bitsDisplay.insert(END,msg)
        self.bitsDisplay.yview(line)
        self.bitsDisplay.configure(text_state=DISABLED)

        self.log = open("log.txt","a")
        self.log.write(msg)
        self.log.close()
-----------------------------------------------------------

I'm passing in a line of text and a line number of 99999 to keep the
vertical scroll bar always at the bottom. But it doesn't appear to be
a problem with the variables. It appears somehow to lose the handle on
the widget that I created. I created it with the following code:

        self.bitsDisplay = Pmw.ScrolledText(bitsFrame,
borderframe=1,labelpos=N,
                                        label_text='RESULTS DISPLAY
WINDOW',
                                        label_fg = 'dark blue',
                                        label_font=(('', '', ''),
'10'),
                                        usehullsize=10,
hull_width=400, hull_height=250,
                                        text_padx=10, text_pady=1,
text_wrap='none')
        self.bitsDisplay.configure(text_state=DISABLED,
text_background="gray90")
        self.bitsDisplay.pack(padx=20)
        bitsFrame.pack(ipady=10)
-------------------------------------------------------------------

Fairly straight-forward. Since it works most of the time, I don't
think it's a problem with my setup. It could be a threading issue. I
just don't have any idea. Any help would be appreciated.

Thanks ahead of time,
Marc