Symptoms
When you try to run a Multidimensional Expressions (MDX) query that uses cell security, the Microsoft SQL Server 2008 Analysis Services server may stop responding. If you run the query in SQL Server Management Studio, you may receive the following error message:

Executing the query
Internal error: An unexpected exception occurred.
Execution completeWhen this problem occurs, the following event may appear in the Application log:
Event Type: Error
Event Source: Instance_Name
Event Category: (256)
Event ID: 22
Date: date
Time: time
User: N/A
Computer: localhost
Description:
The description for Event ID ( 22 ) in Source ( Instance_Name ) cannot be found. The local computer may not have the necessary registry information or message DLL files to display messages from a remote computer. You may be able to use the /AUXSOURCE= flag to retrieve this description; see Help and Support for details. The following information is part of the event: Internal error: An unexpected exception occurred.
Resolution
The fix for this problem was first released in Cumulative Update 1.For more information about how to obtain this cumulative update package for SQL Server 2008, click the following article number to view the article in the Microsoft Knowledge Base:
956717?(http://support.microsoft.com/kb/956717/)Cumulative update package 1 for SQL Server 2008 Note Because the builds are cumulative, each new fix release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2008 fix release. We recommend that you consider applying the most recent fix release that contains this hotfix.For more information, click the following article number to view the article in the Microsoft Knowledge Base:
956909?(http://support.microsoft.com/kb/956909/)The SQL Server 2008 builds that were released after SQL Server 2008 was released