a bug in python windows service?

[momobear]

I feel really puzzled about fellowing code, please help me finger out
what problem here.

import threading

class workingthread(threading.Thread):
      def __init__(self):
            self.quitEvent = threading.Event()
            self.waitTime = 10
	    threading.Thread.__init__(self)

      def run(self):
            while not self.quitEvent.isSet():
                 self.quitEvent.wait(self.waitTime)

      def join(self, timeout = None):
	    self.quitEvent.set()
	    threading.Thread.join(self, timeout)

import win32serviceutil
import win32event

class testTime(win32serviceutil.ServiceFramework):
     _svc_name_ = "testTime"
     _svc_display_name_ = "testTime"
     _svc_deps_ = ["EventLog"]

     def __init__(self, args):
            win32serviceutil.ServiceFramework.__init__(self, args)
            self.hWaitStop = win32event.CreateEvent(None, 0, 0, None)
            self.thread = workingthread()

     def SvcStop(self):
             win32event.SetEvent(self.hWaitStop)

     def SvcDoRun(self):
             self.thread.run()
             win32event.WaitForSingleObject(self.hWaitStop,
win32event.INFINITE)
             self.thread.join()

if __name__ == '__main__':
    win32serviceutil.HandleCommandLine(testTime)

each time I got the fellowing result, anyone can point out what's
wrong in it?

E:\code\monitor2>testTime.py debug
Debugging service testTime- press Ctrl+C to stop.
Stopping debug service.
Error 0xC0000003 - The instance's SvcRun() method failed

  File "C:\Python24\Lib\site-packages\win32\lib\win32serviceutil.py",
line 785,
in SvcRun
    self.SvcDoRun()
  File "E:\code\monitor2\testTime.py", line 35, in SvcDoRun
    self.thread.run()
  File "E:\code\monitor2\testTime.py", line 12, in run
    self.quitEvent.wait(self.waitTime)
  File "C:\Python24\lib\threading.py", line 348, in wait
    self.__cond.wait(timeout)
  File "C:\Python24\lib\threading.py", line 222, in wait
    _sleep(delay)

exceptions.IOError: (4, 'Interrupted function call')