I just tried to checkout the bzr-dbus branch and got something similar, using bzr 1.3.1 on Hardy.  Clearly this looks like a python-dbus problem rather than a bzr problem, but I thought I would add to the canon of known issues.


|> bzr co http://bzr.debian.org/pkg-bazaar/bzr-email/unstable Bzr_Email_Unstable
bzr: ERROR: dbus.exceptions.DBusException: org.freedesktop.DBus.Error.Spawn.ExecFailed: Failed to execute dbus-launch to autolaunch D-Bus session

Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 834, in run_bzr_catch_errors
    return run_bzr(argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 790, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 492, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.5/site-packages/bzrlib/builtins.py", line 1012, in run
    accelerator_tree, hardlink)
  File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 766, in create_checkout
    checkout_branch.pull(self, stop_revision=revision_id)
  File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 165, in write_locked
    return unbound(self, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 1714, in pull
    run_hooks=run_hooks)
  File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 165, in write_locked
    return unbound(self, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 1513, in pull
    self.update_revisions(source, stop_revision, overwrite=overwrite)
  File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 165, in write_locked
    return unbound(self, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 1480, in update_revisions
    other_last_revision)
  File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 165, in write_locked
    return unbound(self, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 1399, in set_last_revision_info
    self.set_revision_history(history)
  File "/usr/lib/python2.5/site-packages/bzrlib/decorators.py", line 165, in write_locked
    return unbound(self, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/bzrlib/branch.py", line 1382, in set_revision_history
    hook(self, rev_history)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/dbus/hook.py", line 41, in on_set_rh
    activity.Activity().advertise_branch(branch)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/dbus/activity.py", line 57, in __init__
    self.bus = _get_bus(bus)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/dbus/activity.py", line 42, in _get_bus
    return dbus.SessionBus()
  File "/var/lib/python-support/python2.5/dbus/_dbus.py", line 217, in __new__
    mainloop=mainloop)
  File "/var/lib/python-support/python2.5/dbus/_dbus.py", line 106, in __new__
    bus = BusConnection.__new__(subclass, bus_type, mainloop=mainloop)
  File "/var/lib/python-support/python2.5/dbus/bus.py", line 125, in __new__
    bus = cls._new_for_bus(address_or_type, mainloop=mainloop)
DBusException: org.freedesktop.DBus.Error.Spawn.ExecFailed: Failed to execute dbus-launch to autolaunch D-Bus session

bzr 1.3.1 on python 2.5.2.final.0 (linux2)
arguments: ['/usr/bin/bzr', 'co', 'http://bzr.debian.org/pkg-bazaar/bzr-email/unstable', 'Bzr_Email_Unstable']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'en_GB.UTF-8'
plugins:
  builddeb             /usr/lib/python2.5/site-packages/bzrlib/plugins/builddeb [0.92.0dev0]
  bzrtools             /usr/lib/python2.5/site-packages/bzrlib/plugins/bzrtools [1.3.0]
  dbus                 /usr/lib/python2.5/site-packages/bzrlib/plugins/dbus [unknown]
  launchpad            /usr/lib/python2.5/site-packages/bzrlib/plugins/launchpad [unknown]
  svn                  /usr/lib/python2.5/site-packages/bzrlib/plugins/svn [0.4.9]
  xmloutput            /home/users/russel/.bazaar/plugins/xmloutput [0.4.3]
*** 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.