pymongo error operation failure

I'm currently using celery with django, i have pymongo ver 1.11 mongodb ver 1.8

I'm getting following error, i'm not able to figure out what is the error.

[2011-09-23 02:06:59,544: WARNING/MainProcess] File "/usr/local/lib/python2.6/dist-packages/pymongo/database.py", line 293, in command
[2011-09-23 02:06:59,560: WARNING/MainProcess] msg, allowable_errors)
[2011-09-23 02:06:59,560: WARNING/MainProcess] File "/usr/local/lib/python2.6/dist-packages/pymongo/helpers.py", line 126, in _check_command_response
[2011-09-23 02:06:59,561: WARNING/MainProcess] raise OperationFailure(msg % response["errmsg"])
[2011-09-23 02:06:59,561: WARNING/MainProcess] pymongo.errors
[2011-09-23 02:06:59,561: WARNING/MainProcess] .
[2011-09-23 02:06:59,561: WARNING/MainProcess] OperationFailure
[2011-09-23 02:06:59,561: WARNING/Main开发者_StackOverflow社区Process] :
[2011-09-23 02:06:59,561: WARNING/MainProcess] command SON([('findandmodify', 'messages'), ('query', {'queue': 'celery'}), ('remove', True)]) failed: exception: nextSafe(): { $err: "using a newer index version: { v: 1, key: { queue: 1 }, ns: "kombu_def...", code: 13658 }

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I think its to do with MongoDB indexes are using version 1 which relates to mongodb >= 2.0

see: http://www.mongodb.org/display/DOCS/Index+Versions