I'm getting the following error on Windows in an application I've
written (the error does not occur on Linux):

Exception in thread Thread-4:
Traceback (most recent call last):
 File "C:\Python26\lib\threading.py", line 525, in __bootstrap_inner
   self.run()
 File "C:\Documents and Settings\David\My
Documents\pyzui\pyzui\tileprovider.py", line 97, in run
   self.__tilecache[tile_id] = Tile(tile)
 File "C:\Documents and Settings\David\My
Documents\pyzui\pyzui\tilecache.py", line 165, in __setitem__
   with self.__lock:
 File "C:\Python26\lib\threading.py", line 115, in acquire
   me = current_thread()
 File "C:\Python26\lib\threading.py", line 803, in currentThread
   return _active[_get_ident()]
OverflowError: can't convert negative value to unsigned long

Where __lock is an RLock object.

The odd thing is that it only affects a single class (which is derived
from the TileProvider class in tileprovider.py, which in turn is derived
from threading.Thread). This led me to believe there was an error in my
code, but I asked on the mailing list and was told that it is likely a
bug in the threading module.

The Python version is 2.6.2.