Generate catalog (AZW3) fails with added prefix rule

Generate catalog (AZW3) fails processing an added prefix rule.
To test, I created a new library and added two books.
One book has no tags, the other has the tag "Cooking".
The only prefix rule is to add a prefix for books with the tag "Cooking".

OS is Win7 Pro 64 bit.

calibre, version 0.9.3 (win32, isfrozen: True)
Conversion Error: Failed: Generate catalog

Generate catalog
 Sections: Authors, Titles, Series
Catalog_EPUB_MOBI(): Generating azw3 for kindle in GUI environment, locale: 'en'
 connected_device: 'None'
 book count: 2
 opts:
  author_clip: 60
  catalog_title: u"'Test' Catalog"
  connected_kindle: False
  creator: u'Monday, October 22, 2012'
  description_clip: 100
  exclude_genre: u'\\[.+\\]|^\\+$'
  exclusion_rules: ()
  fmt: u'azw3'
  header_note_source_field: ''
  merge_comments_rule: '::True'
  output_profile: 'kindle'
  prefix_rules: ((u'Cooking', u'Tags', u'Cooking', u'\u25ca'),)
  search_text: None
  sort_by: None
  sort_descriptions_by_author: True
  sync: False
  thumb_width: u'1.00'
  use_existing_cover: False
 Added prefixes:
Python function terminated unexpectedly
  _log_prefix_rule_match_info() takes exactly 3 arguments (2 given) (Error Code: 1)
Traceback (most recent call last):
  File "site.py", line 132, in main
  File "site.py", line 109, in run_entry_point
  File "site-packages\calibre\utils\ipc\worker.py", line 186, in main
  File "site-packages\calibre\gui2\convert\gui_conversion.py", line 68, in gui_catalog
  File "site-packages\calibre\library\catalogs\epub_mobi.py", line 333, in run
  File "site-packages\calibre\library\catalogs\epub_mobi_builder.py", line 153, in __init__
  File "site-packages\calibre\library\catalogs\epub_mobi_builder.py", line 979, in fetch_books_to_catalog
  File "site-packages\calibre\library\catalogs\epub_mobi_builder.py", line 920, in _populate_title
  File "site-packages\calibre\library\catalogs\epub_mobi_builder.py", line 585, in discover_prefix
TypeError: _log_prefix_rule_match_info() takes exactly 3 arguments (2 given)