This is from mercurial-stable-snapshot downloaded Nov 4, 2007, Subversion 
version version 1.4.3 (r23084), on Kubuntu Feisty.  While trying to convert a 
Subversion repository, hg crashes, and recommends that I submit a bug report.

ser@bean:~$ hg convert file:///home/ser/rexml-svn rexml-hg
initializing destination rexml-hg repository
scanning source...
** unknown exception encountered, details follow
** report bug details to http://www.selenic.com/mercurial/bts
** or mercurial@selenic.com
** Mercurial Distributed SCM (version unknown)
Traceback (most recent call last):
  File "/usr/bin/hg", line 14, in <module>
    mercurial.dispatch.run()
  File "/usr/lib/python2.5/site-packages/mercurial/dispatch.py", line 20, in 
run
    sys.exit(dispatch(sys.argv[1:]))
  File "/usr/lib/python2.5/site-packages/mercurial/dispatch.py", line 29, in 
dispatch
    return _runcatch(u, args)
  File "/usr/lib/python2.5/site-packages/mercurial/dispatch.py", line 45, in 
_runcatch
    return _dispatch(ui, args)
  File "/usr/lib/python2.5/site-packages/mercurial/dispatch.py", line 348, in 
_dispatch
    ret = _runcommand(ui, options, cmd, d)
  File "/usr/lib/python2.5/site-packages/mercurial/dispatch.py", line 401, in 
_runcommand
    return checkargs()
  File "/usr/lib/python2.5/site-packages/mercurial/dispatch.py", line 357, in 
checkargs
    return cmdfunc()
  File "/usr/lib/python2.5/site-packages/mercurial/dispatch.py", line 342, in 
<lambda>
    d = lambda: func(ui, *args, **cmdoptions)
  File "/usr/lib/python2.5/site-packages/hgext/convert/__init__.py", line 380, 
in convert
    c.convert()
  File "/usr/lib/python2.5/site-packages/hgext/convert/__init__.py", line 257, 
in convert
    parents = self.walktree(heads)
  File "/usr/lib/python2.5/site-packages/hgext/convert/__init__.py", line 97, 
in walktree
    commit = self.cachecommit(n)
  File "/usr/lib/python2.5/site-packages/hgext/convert/__init__.py", line 204, 
in cachecommit
    commit = self.source.getcommit(rev)
  File "/usr/lib/python2.5/site-packages/hgext/convert/subversion.py", line 
245, in getcommit
    self._fetch_revisions(from_revnum=revnum, to_revnum=stop)
  File "/usr/lib/python2.5/site-packages/hgext/convert/subversion.py", line 
620, in _fetch_revisions
    for entry in self.get_log([self.module], from_revnum, to_revnum):
  File "/usr/lib/python2.5/site-packages/hgext/convert/subversion.py", line 
275, in get_log
    for p in parent(stdout):
  File "/usr/lib/python2.5/site-packages/hgext/convert/subversion.py", line 
262, in parent
    raise SubversionException("child raised exception", entry)
libsvn._core.SubversionException: ('child raised exception', 160013)