Can't convert files

When I try to convert a file I get this error:

calibre, version 0.8.9
ERROR: Unhandled exception: <b>KeyError</b>:'completion_change_to_ascii_sorting'

Traceback (most recent call last):
File "site-packages\calibre\gui2\actions\convert.py", line 109, in convert_ebook
File "site-packages\calibre\gui2\tools.py", line 41, in convert_single_ebook
File "site-packages\calibre\gui2\convert\single.py", line 126, in __init__
File "site-packages\calibre\gui2\convert\single.py", line 172, in setup_pipeline
File "site-packages\calibre\gui2\convert\single.py", line 169, in widget_factory
File "site-packages\calibre\gui2\convert\metadata.py", line 59, in __init__
File "site-packages\calibre\gui2\convert\metadata.py", line 72, in initialize_metadata_options
File "site-packages\calibre\gui2\convert\metadata.py", line 103, in initialize_combos
File "site-packages\calibre\gui2\convert\metadata.py", line 113, in initalize_authors
File "site-packages\calibre\gui2\complete.py", line 174, in update_items_cache
File "site-packages\calibre\gui2\complete.py", line 85, in update_items_cache
File "site-packages\calibre\gui2\complete.py", line 155, in fset
File "site-packages\calibre\gui2\complete.py", line 26, in set_items
KeyError: 'completion_change_to_ascii_sorting'

I've done a repair install with no success. I would appreciate any assistance.