No handlers could be found for logger "bzr"

Dear all,

I am new to UCS. I just installed it as described on http://ubuntu-component-store.readthedocs.org/en/latest/install.html and tried to install a component:

ucs install PageWithBottomEdge

This is what I get:

sven@borghardt:bin$ sudo ucs search PageWithBottomEdge
Matching curated components
===========================
No handlers could be found for logger "bzr"
Traceback (most recent call last):
  File "/usr/bin/ucs", line 531, in <module>
    args.func(args)
  File "/usr/bin/ucs", line 480, in cmd_search
    results = cu.search(args.query)
  File "/usr/bin/ucs", line 347, in search
    component_metadata = self.__update_metadata_if_required()
  File "/usr/bin/ucs", line 311, in __update_metadata_if_required
    in tree.list_files(from_dir=self.COMPONENTS_ROOT)
  File "/usr/lib/python2.7/dist-packages/bzrlib/revisiontree.py", line 146, in list_files
    inv, from_dir_id = self._path2inv_file_id(from_dir)
  File "/usr/lib/python2.7/dist-packages/bzrlib/tree.py", line 821, in _path2inv_file_id
    return self.root_inventory, self.root_inventory.path2id(path)
  File "/usr/lib/python2.7/dist-packages/bzrlib/inventory.py", line 2120, in path2id
    items = parent_id_index.iteritems(key_filter)
  File "/usr/lib/python2.7/dist-packages/bzrlib/chk_map.py", line 514, in iteritems
    self._ensure_root()
  File "/usr/lib/python2.7/dist-packages/bzrlib/chk_map.py", line 163, in _ensure_root
    self._root_node = self._get_node(self._root_node)
  File "/usr/lib/python2.7/dist-packages/bzrlib/chk_map.py", line 176, in _get_node
    bytes = self._read_bytes(node)
  File "/usr/lib/python2.7/dist-packages/bzrlib/chk_map.py", line 187, in _read_bytes
    bytes = stream.next().get_bytes_as('fulltext')
  File "/usr/lib/python2.7/dist-packages/bzrlib/groupcompress.py", line 1456, in get_record_stream
    orig_keys, ordering, include_delta_closure):
  File "/usr/lib/python2.7/dist-packages/bzrlib/groupcompress.py", line 1562, in _get_remaining_record_stream
    locations = self._index.get_build_details(keys)
  File "/usr/lib/python2.7/dist-packages/bzrlib/groupcompress.py", line 2129, in get_build_details
    self._check_read()
  File "/usr/lib/python2.7/dist-packages/bzrlib/groupcompress.py", line 2051, in _check_read
    raise errors.ObjectNotLocked(self)
bzrlib.errors.ObjectNotLocked: <bzrlib.groupcompress._GCGraphIndex object at 0x7f2df7c97a10> is not locked

Can anyone tell me, what I did wrong?

Best regards!