AttributeError: 'BuildProperties' object has no attribute 'target_dir'

I get this on my ubuntu intrepid:

bigon@imladris:~/Developpement/tp-python-exp$ bzr-buildpackage --merge
Building using working tree
Running in merge mode
Preparing the build area: ../build-area
Exporting to ../build-area/telepathy-python-0.15.2 in merge mode
Looking for /home/bigon/Developpement/tarballs/telepathy-python_0.15.2.orig.tar.gz to use as upstream source
For compatibility looking for ../tarballs/telepathy-python_0.15.2.orig.tar.gz to use as upstream source
Using uscan to look for the upstream tarball
bzr: ERROR: exceptions.AttributeError: 'BuildProperties' object has no attribute 'target_dir'

Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 857, in run_bzr_catch_errors
    return run_bzr(argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 797, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.5/site-packages/bzrlib/commands.py", line 499, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/builddeb/__init__.py", line 357, in run
    build.export(use_existing)
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/builddeb/builder.py", line 399, in export
    tarball = self._find_tarball()
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/builddeb/builder.py", line 262, in _find_tarball
    self._get_upstream_from_watch()
  File "/usr/lib/python2.5/site-packages/bzrlib/plugins/builddeb/builder.py", line 202, in _get_upstream_from_watch
    self._properties.target_dir()))
AttributeError: 'BuildProperties' object has no attribute 'target_dir'

bzr 1.6.1 on python 2.5.2 (linux2)
arguments: ['/usr/bin/bzr', 'builddeb', '--merge']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'fr_BE.UTF-8'
plugins:
  builddeb /usr/lib/python2.5/site-packages/bzrlib/plugins/builddeb [2.0.2]
  bzrtools /usr/lib/python2.5/site-packages/bzrlib/plugins/bzrtools [1.6.0]
  launchpad /usr/lib/python2.5/site-packages/bzrlib/plugins/launchpad [unknown]