strange exception

Does anyone has any idea that in what conditions this exception can occur ?

  File "C:\Python27\lib\site-packages\zope\app\component\hooks.py", line 89, 
in getSiteManager
    context, zope.component.getGlobalSiteManager())
  File "C:\Python27\lib\site-packages\zope\app\component\hooks.py", line 95, 
in adapter_hook
    return siteinfo.adapter_hook(interface, object, name, default)
  File "C:\Python27\lib\site-packages\zope\app\component\site.py", line 407, 
in SiteManagerAdapter
    current = getattr(current, '__parent__', None)
  File 
"C:\Python27\lib\site-packages\zodb-4.4.3-py2.7.egg\ZODB\Connection.py", 
line 899, in setstate
    self._setstate(obj, oid)
  File 
"C:\Python27\lib\site-packages\zodb-4.4.3-py2.7.egg\ZODB\Connection.py", 
line 943, in _setstate
    p, serial = self._storage.load(oid, '')
  File 
"C:\Python27\lib\site-packages\zeo-4.3.0-py2.7.egg\ZEO\ClientStorage.py", 
line 825, in load
    result = self.loadBefore(oid, m64)
  File 
"C:\Python27\lib\site-packages\zeo-4.3.0-py2.7.egg\ZEO\ClientStorage.py", 
line 851, in loadBefore
    self._cache.store(oid, tid, end, data)
  File "C:\Python27\lib\site-packages\zeo-4.3.0-py2.7.egg\ZEO\cache.py", 
line 139, in _locked_wrapper
    return func(inst, *args, **kwargs)
  File "C:\Python27\lib\site-packages\zeo-4.3.0-py2.7.egg\ZEO\cache.py", 
line 647, in store
    self._store(oid, start_tid, end_tid, data, size)
  File "C:\Python27\lib\site-packages\zeo-4.3.0-py2.7.egg\ZEO\cache.py", 
line 661, in _store
    nfreebytes = self._makeroom(size+1)
  File "C:\Python27\lib\site-packages\zeo-4.3.0-py2.7.egg\ZEO\cache.py", 
line 447, in _makeroom
    del current[oid]
  File "C:\Python27\lib\site-packages\zodb-4.4.3-py2.7.egg\ZODB\fsIndex.py", 
line 167, in __delitem__
    del tree[key[6:]]
KeyError: '_\t'

-- 
You received this message because you are subscribed to the Google Groups "zodb" group.
To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
For more options, visit https://groups.google.com/d/optout.