starting mercurial operation

remoteFailed: [Failure instance: Traceback from remote host -- Traceback (most recent call last):
  File "C:\Python25\lib\site-packages\twisted\internet\defer.py", line 106, in maybeDeferred
    result = f(*args, **kw)
  File "C:\Python25\lib\site-packages\buildbot-0.7.11p3-py2.5.egg\buildbot\slave\commands.py", line 1402, in start
    d.addCallback(self.doClobber, self.srcdir)
  File "C:\Python25\lib\site-packages\twisted\internet\defer.py", line 195, in addCallback
    callbackKeywords=kw)
  File "C:\Python25\lib\site-packages\twisted\internet\defer.py", line 186, in addCallbacks
    self._runCallbacks()
--- <exception caught here> ---
  File "C:\Python25\lib\site-packages\twisted\internet\defer.py", line 328, in _runCallbacks
    self.result = callback(self.result, *args, **kw)
  File "C:\Python25\lib\site-packages\buildbot-0.7.11p3-py2.5.egg\buildbot\slave\commands.py", line 1561, in doClobber
    rmdirRecursive(d)
  File "C:\Python25\lib\site-packages\buildbot-0.7.11p3-py2.5.egg\buildbot\slave\commands.py", line 130, in rmdirRecursive
    os.rmdir(dir)
exceptions.WindowsError: [Error 32] The process cannot access the file because it is being used by another process: 'C:\\buildbot-tpd\\tpd-inc\\build'
]