[Zope] Error in upgrade ZCatalog

[Howard Zhang]

Hi there
  I met a problem when i upgrade zope from 2.3.0 to 2.3.1 .
  If i search "tractor" in PTK search field ( right top ). I get an
error :
=20
Error type	 TypeError=09
Error value	 expected integer key=09
Error trace back	=20
Traceback (innermost last):

  File /zope/zope-dc-2.3.1/lib/python/ZPublisher/Publish.py, line 171,
in publish

  File /zope/zope-dc-2.3.1/lib/python/ZPublisher/mapply.py, line 160, in
mapply

    (Object: search)

  File /zope/zope-dc-2.3.1/lib/python/ZPublisher/Publish.py, line 112,
in call_object

    (Object: search)

  File /zope/zope-dc-2.3.1/lib/python/OFS/DTMLMethod.py, line 189, in
__call__

    (Object: search)

  File /zope/zope-dc-2.3.1/lib/python/DocumentTemplate/DT_String.py,
line 538, in __call__

    (Object: search)

  File /zope/zope-dc-2.3.1/lib/python/DocumentTemplate/DT_In.py, line
480, in renderwb

    (Object: portal_catalog)

  File /zope/zope-dc/lib/python/Products/PTKBase/CatalogTool.py, line
163, in searchResults

    (Object: Traversable)

  File /zope/zope-dc-2.3.1/lib/python/Products/ZCatalog/ZCatalog.py,
line 535, in searchResults

    (Object: Traversable)

  File /zope/zope-dc-2.3.1/lib/python/Products/ZCatalog/Catalog.py, line
651, in searchResults

  File /zope/zope-dc-2.3.1/lib/python/Products/ZCatalog/Catalog.py, line
542, in _indexedSearch

  File /zope/zope-dc-2.3.1/lib/python/SearchIndex/UnTextIndex.py, line
513, in _apply_index

  File /zope/zope-dc-2.3.1/lib/python/SearchIndex/UnTextIndex.py, line
576, in query

  File /zope/zope-dc-2.3.1/lib/python/SearchIndex/UnTextIndex.py, line
616, in evaluate

  File /zope/zope-dc-2.3.1/lib/python/SearchIndex/UnTextIndex.py, line
448, in __getitem__

TypeError: expected integer key
=20
=20
What should i do?
=20
thanks