Can'r run BLT twice?

[Todd Krein]

I'm running PythonWin on XP. When I run my plotter program the first
time, it works fine. The second time I run it, I get the following
error. If I exit PythonWin, and restart, I can again run it once. Any
ideas?

Error: 1
TclError Exception in Tk callback
  Function: <bound method PathEval.doOpenTrace of <__main__.PathEval
instance at 0x0127AC60>> (type: <type 'instancemethod'>)
  Args: ()
Traceback (innermost last):
  File "C:\Python24\lib\Pmw\Pmw_1_2\lib\PmwBase.py", line 1747, in
__call__
    None
  File
"C:\NBU\perforce\hardware\test\home_survey\data\home_007\raw_data\KitchenToDen\AMPLITUDE\PathEval.py",
line 89, in doOpenTrace
    self.doPlotTrace()                          # go plot the thing
  File
"C:\NBU\perforce\hardware\test\home_survey\data\home_007\raw_data\KitchenToDen\AMPLITUDE\PathEval.py",
line 117, in doPlotTrace
    self.graph = Pmw.Blt.Graph(tkRoot)                   # make a new
graph area
  File "C:\Python24\lib\Pmw\Pmw_1_2\lib\PmwBlt.py", line 260, in
__init__
    None
  File "C:\Python24\lib\lib-tk\Tkinter.py", line 1861, in __init__
    self.tk.call(
TclError: invalid command name "::blt::graph"