ReadOnlyError when doing a status against another branch

bzr status -r branch:../barbaz
bzr: ERROR: bzrlib.errors.ReadOnlyError: A write attempt was made in a read only transaction on KnitPackRepository('file:///net/software/projects/foo/.bzr/repository/')

Traceback (most recent call last):
  File "/usr/local/lib/python2.5/site-packages/bzrlib/commands.py", line 834, in run_bzr_catch_errors
    return run_bzr(argv)
  File "/usr/local/lib/python2.5/site-packages/bzrlib/commands.py", line 790, in run_bzr
    ret = run(*run_argv)
  File "/usr/local/lib/python2.5/site-packages/bzrlib/commands.py", line 492, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/local/lib/python2.5/site-packages/bzrlib/commands.py", line 800, in ignore_pipe
    result = func(*args, **kwargs)
  File "/usr/local/lib/python2.5/site-packages/bzrlib/builtins.py", line 189, in run
    to_file=self.outf, short=short, versioned=versioned)
  File "/usr/local/lib/python2.5/site-packages/bzrlib/status.py", line 87, in show_tree_status
    rev_id = revision[0].in_history(wt.branch).rev_id
  File "/usr/local/lib/python2.5/site-packages/bzrlib/revisionspec.py", line 225, in in_history
    return self._match_on_and_check(branch, revs)
  File "/usr/local/lib/python2.5/site-packages/bzrlib/revisionspec.py", line 207, in _match_on_and_check
    info = self._match_on(branch, revs)
  File "/usr/local/lib/python2.5/site-packages/bzrlib/revisionspec.py", line 687, in _match_on
    branch.fetch(other_branch, revision_b)
  File "/usr/local/lib/python2.5/site-packages/bzrlib/decorators.py", line 163, in write_locked
    self.lock_write()
  File "/usr/local/lib/python2.5/site-packages/bzrlib/branch.py", line 1325, in lock_write
    repo_token = self.repository.lock_write()
  File "/usr/local/lib/python2.5/site-packages/bzrlib/repofmt/pack_repo.py", line 2032, in lock_write
    raise errors.ReadOnlyError(self)
ReadOnlyError: A write attempt was made in a read only transaction on KnitPackRepository('file:///net/software/projects/foo/.bzr/repository/')

bzr 1.3.1 on python 2.5.1.final.0 (linux2)
arguments: ['/usr/local/bin/bzr', 'status', '-r', 'branch:../barbaz']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'en_US.UTF-8'
plugins:
  launchpad /usr/local/lib/python2.5/site-packages/bzrlib/plugins/launchpad [unknown]
*** Bazaar has encountered an internal error.
    Please report a bug at https://bugs.launchpad.net/bzr/+filebug
    including this traceback, and a description of what you
    were doing when the error occurred.