Error in TFS Reports. Query execution failed for data set 'dsLastProcessedTime'

When upgrade to SQL Server 2008, the SQL Server that use the TFS to show the reports present the following message:

Query execution failed for data set 'dsLastProcessedTime'.

To resolve this problem, you need to do the following:

1. Go to the following Address http://server/Reports
2. Select the Data Source TfsOlapReportsDS
3. Check the option 'Enable This Data Source'
4. In Data Source Type, select 'Microsoft SQL Server Analysis Services'
5. In Connection String, write 'Data source=[servername]; initial catalog=TfsWarehouse' (without ')
6. Check 'Credentials stored securely in the report server', and type the user name [domain\user] and the password for the user in the domain who has access to the server of analysis Services.
7. Check 'Use as Windows Credentials ...' and 'Impersonate the authenticated user...' and click the botton Apply.

After that, do the same for the Data Source TfsReportDS, with the following exceptions

1. In the Data Source Type, select Microsoft SQL Server.
2. In the Connection String write 'Data Source=[servername]; initial catalog=TfsWarehouse'.

Use the same configuration used in the Data Source TfsOlapReportDS.

With that, the reports should be showed again.