Problem with permissions "Error..."



Hi,
Im unable to menage permissions for my cubes.
I recieve following error while trying to change user permission
configuration.

"Error occurred while processing security for cube 'Sales' (Security
Error)

I use MS SQL 2000 with SP3 for AS and SQLServer.
All what I have found on microsoft pages is that I need to install SP
(but I have already one).
How can I resolve such a problem ?

regards
Peter

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