exception in pushing via olive-gtk

activating push button gives following traceback:

Traceback (most recent call last):
  File "/usr/local/lib/python2.4/site-packages/olive/__init__.py", line 565, in on_menuitem_branch_push_activate
    push = PushDialog(self.wt.branch, self.window)
  File "/usr/local/lib/python2.4/site-packages/bzrlib/plugins/gtk/push.py", line 75, in __init__
    self._history = UrlHistory(self.branch.get_config(), 'push_history')
AttributeError: 'NoneType' object has no attribute 'get_config'

using command line bzr in the same directory works fine:

(hsn@ttyp1):~/sf/scache% bzr push
Using saved location: sftp://<email address hidden>/home/groups/s/sc/scache/htdocs/bazaar-ng/scache--head/
No new revisions to push.

bzr-gtk 0.18