An unhandled exception found

Submit this bug here: https://sourceforge.net/tracker/?func=add&group_id=170274&atid=853652

Python version:
2.7.3 (default, Jan 2 2013, 16:53:07)
[GCC 4.7.2]

GTK version:2.24.10
PyGTK version:2.24.0

w3af - Web Application Attack and Audit Framework
Version: 1.1 (from Debian Package 1.0-rc3svn3489-1)
Author: Andres Riancho and the w3af team.Traceback (most recent call last):
File \"/usr/share/w3af/core/ui/gtkUi/main.py\", line 590, in startScanWrap
self.w3af.start()
File \"/usr/share/w3af/core/controllers/w3afCore.py\", line 417, in start
self._realStart()
File \"/usr/share/w3af/core/controllers/w3afCore.py\", line 602, in _realStart
self._end( e )
File \"/usr/share/w3af/core/controllers/w3afCore.py\", line 676, in _end
tm.join( joinAll=True )
File \"/usr/share/w3af/core/controllers/threads/threadManager.py\", line 119, in join
self._threadPool.wait( ownerObj, joinAll )
File \"/usr/share/w3af/core/controllers/threads/threadpool.py\", line 260, in wait
self.poll(block=True, ownerObj=ownerObj, joinAll=joinAll)
File \"/usr/share/w3af/core/controllers/threads/threadpool.py\", line 245, in poll
raise result
w3afException: w3afMustStopException found by _send_404, someone else will handle it.