I get a similar bug with my Karmic setup. On a "bzr up," I receive the following error:

bzr: ERROR: exceptions.StopIteration:  

Selections from the crash log:

ProblemType: Crash
BzrDebugFlags: set()
BzrPlugins:
   bzrtools             /usr/lib/python2.6/dist-packages/bzrlib/plugins/bzrtools [2.0.1]
   extmerge             /u/eitan/.bazaar/plugins/extmerge [unknown]
   fastimport           /usr/lib/python2.6/dist-packages/bzrlib/plugins/fastimport [0.9.0dev]
   launchpad            /usr/lib/python2.6/dist-packages/bzrlib/plugins/launchpad [2.0.2]
   netrc_credential_store /usr/lib/python2.6/dist-packages/bzrlib/plugins/netrc_credential_store [2.0.2]
   rebase               /usr/lib/python2.6/dist-packages/bzrlib/plugins/rebase [0.5.3]
   svn                  /usr/lib/python2.6/dist-packages/bzrlib/plugins/svn [1.0.0dev]
BzrVersion: 2.0.2
CommandLine: ['/usr/bin/bzr', 'up']
Date: Mon Feb 22 15:46:59 2010
FileSystemEncoding: UTF-8
Locale: en_US.UTF-8
Platform: Linux-2.6.31-19-generic-x86_64-with-Ubuntu-9.10-karmic

-----

PythonVersion: 2.6.4
Traceback:
 Traceback (most recent call last):
   File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 842, in exception_to_return_code
     return the_callable(*args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 1037, in run_bzr
     ret = run(*run_argv)
   File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 654, in run_argv_aliases
     return self.run(**all_cmd_args)
   File "/usr/lib/python2.6/dist-packages/bzrlib/builtins.py", line 1413, in run
     view_info=view_info), possible_transports=possible_transports)
   File "/usr/lib/python2.6/dist-packages/bzrlib/workingtree.py", line 2213, in update
     old_tip = self.branch.update(possible_transports)
   File "/usr/lib/python2.6/dist-packages/bzrlib/decorators.py", line 192, in write_locked
     result = unbound(self, *args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/branch.py", line 2437, in update
     self.pull(master, overwrite=True)
   File "/usr/lib/python2.6/dist-packages/bzrlib/decorators.py", line 192, in write_locked
     result = unbound(self, *args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/branch.py", line 948, in pull
     possible_transports=possible_transports, *args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/svn/branch.py", line 730, in pull
     self.update_revisions(stop_revision, overwrite)
   File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/svn/branch.py", line 665, in update_revisions
     mapping=self.source.mapping)
   File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/svn/fetch.py", line 1271, in fetch
     use_replay=self._use_replay)
   File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/svn/fetch.py", line 1201, in _fetch_revisions
     parent_revmeta)
   File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/svn/fetch.py", line 1146, in _fetch_revision_switch
     report_inventory_contents(reporter, parent_revnum, start_empty)
   File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/svn/errors.py", line 134, in convert
     return unbound(*args, **kwargs)
   File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/svn/fetch.py", line 912, in report_inventory_contents
     reporter.finish()
   File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/svn/fetch.py", line 348, in open_file
     return self._open_file(path, base_revnum)
   File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/svn/fetch.py", line 517, in _open_file
     base_file_id = self.editor._get_old_id(self.old_id, path)
   File "/usr/lib/python2.6/dist-packages/bzrlib/plugins/svn/fetch.py", line 775, in _get_old_id
     return ret.next()[1]
 StopIteration