SQL Server 2008 management tool and MSXML6 sp2 question

I've posted my problem in a few other categories.  Sorry for that.  I didn't see the security category until now.

I'm trying to use ASP.NET's built-in role/user management for a couple ASP.NET MVC 2 sites.  I'm using the MVCMusicStore as my guide.  I click on the Configuration Tool as the tutorial suggests, which launches the site administration page.  Unfortunately when I click on the security tab, I get an error that it cannot connect to the data store.  Attempting to test the AspNetSqlProvider gives me a similar error.

I've run the aspnet_regsql program as the error message suggested, and I have a role/user management database ready to go on the server.  The proper tables are constructed, and all that.  The configuration tool still doesn't see the data store.

As a test, I ran the MVCMusicStore demo in the debugger.  Its role/user management functionality worked.  I was able to add myself as a customer, and add/remove items from my cart with no errors or exceptions.  However, when I attempted to access its security tab in the configuration tool, I received the same error as I get for my own project.  How is it possible that role/user management works, but the configuration tool cannot change its settings?

Any suggestions on how I can get the configuration t

I just installed SQL Server 2008 Management studio Express on my Vista machine.

i tried connecting to local machine using :

.\sqlexpress, (local)\sqlexpress, or .\SQLExpress, MyPCNAME\SQLExpress

nothing is working, getting this error:

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Cannot connect to PC-NAME\SQLEXPRESS. A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
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