You've changed the connection string (web.config) entry that points at the membership schema. "Out of the box", the Personal Starter Kit comes with two SQL express databases under \APP_DATA: Personal.mdf and ASPNETDB.mdf. The ASPNETDB.mdf has the membership schema, including the stored procedure your error is failing to find.

A fresh install of the kit sets LocalSQLServer to point at ASPNETDB with integrated security. You've changed the database and also the security setting. I guess that you've switched to SQL Server (instead of SQL Express)? That's fine - but you need to install the membership schema into the SQL Server database.

If you've created a SQL Server database named PERSONAL, then you need to run the aspnet_regsql.exe wizard to install the membership schema into it. Scott Guthrie walks through this process: http://weblogs.asp.net/scottgu/archive/2005/08/25/423703.aspx