AttributeError: 'module' object has no attribute 'builtins'

zr co --lightweight lp:~ollie-petch/bzr-oodiff/trunk bzr_oodiff
cannot import name InterBranch
Unable to load plugin 'svn' from '/usr/lib/python2.6/dist-packages/bzrlib/plugins'
cannot import name InterBranch
Unable to load plugin 'search' from '/usr/lib/python2.6/dist-packages/bzrlib/plugins'
'module' object has no attribute 'builtins'
Unable to load plugin 'launchpad' from '/usr/lib/python2.6/dist-packages/bzrlib/plugins'
cannot import name InterBranch
Unable to load plugin 'dbus' from '/usr/lib/python2.6/dist-packages/bzrlib/plugins'
cannot import name InterBranch
Unable to load plugin 'gtk' from '/usr/lib/python2.6/dist-packages/bzrlib/plugins'
'module' object has no attribute 'builtins'
Unable to load plugin 'qbzr' from '/usr/lib/python2.6/dist-packages/bzrlib/plugins'
'module' object has no attribute 'builtins'
Unable to load plugin 'upload' from '/usr/lib/python2.6/dist-packages/bzrlib/plugins'
cannot import name InterBranch
Unable to load plugin 'avahi' from '/usr/lib/python2.6/dist-packages/bzrlib/plugins'
'module' object has no attribute 'builtins'
Unable to load plugin 'fastimport' from '/usr/lib/python2.6/dist-packages/bzrlib/plugins'
cannot import name InterBranch
Unable to load plugin 'email' from '/usr/lib/python2.6/dist-packages/bzrlib/plugins'
bzr: ERROR: exceptions.AttributeError: 'module' object has no attribute 'builtins'

Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 835, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 1008, in run_bzr
    cmd_obj = get_cmd_object(cmd, plugins_override=not opt_builtin)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 210, in get_cmd_object
    return _get_cmd_object(cmd_name, plugins_override)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 230, in _get_cmd_object
    cmd = hook(cmd, cmd_name)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 277, in _get_bzr_command
    cmds = _builtin_commands()
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 140, in _builtin_commands
    import bzrlib.builtins
  File "/usr/lib/python2.6/dist-packages/bzrlib/builtins.py", line 5707, in <module>
    from bzrlib.foreign import cmd_dpush
  File "/usr/lib/python2.6/dist-packages/bzrlib/foreign.py", line 21, in <module>
    from bzrlib.branch import (
  File "/usr/lib/python2.6/dist-packages/bzrlib/branch.py", line 2027, in <module>
    __format7 = BzrBranchFormat7()
  File "/usr/lib/python2.6/dist-packages/bzrlib/branch.py", line 1869, in __init__
    RepositoryFormatKnitPack5RichRoot()
  File "/usr/lib/python2.6/dist-packages/bzrlib/lazy_import.py", line 122, in __call__
    obj = _replace()
  File "/usr/lib/python2.6/dist-packages/bzrlib/lazy_import.py", line 89, in _replace
    obj = factory(self, scope, name)
  File "/usr/lib/python2.6/dist-packages/bzrlib/lazy_import.py", line 192, in _import
    module = __import__(module_python_path, scope, scope, [member])
  File "/usr/lib/python2.6/dist-packages/bzrlib/repofmt/pack_repo.py", line 58, in <module>
    from bzrlib.btree_index import (
  File "/usr/lib/python2.6/dist-packages/bzrlib/btree_index.py", line 20, in <module>
    from bisect import bisect_right
  File "/var/devel_linux/bzr_plugins/bisect/__init__.py", line 455, in <module>
    register_command(cmd_bisect)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 128, in register_command
    return plugin_cmds.register(cmd, decorate)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 98, in register
    previous = _builtin_commands().get(k_unsquished)
  File "/usr/lib/python2.6/dist-packages/bzrlib/commands.py", line 141, in _builtin_commands
    return _scan_module_for_commands(bzrlib.builtins)
AttributeError: 'module' object has no attribute 'builtins'

bzr 1.17 on python 2.6.2 (linux2)
arguments: ['/usr/bin/bzr', 'co', '--lightweight', 'lp:~ollie-petch/bzr-oodiff/trunk', 'bzr_oodiff']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'de_DE.UTF-8'
plugins:
  builddeb /usr/lib/python2.6/dist-packages/bzrlib/plugins/builddeb [unknown]
  bzrtools /usr/lib/python2.6/dist-packages/bzrlib/plugins/bzrtools [1.17]
  netrc_credential_store /usr/lib/python2.6/dist-packages/bzrlib/plugins/netrc_credential_store [1.17]
*** 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.