Take a look at your web.config file. Depending on your environment setup, whether you are using ASP.Net v2.0 or ASP.Net v1.x, what version of SQL, or what type of module you are adding, you'll need to modify your connection strings to allow for the proper key to be used to connect to your database.
In my case, using SQLv2005, ASP.Net v2.0, and this FAQ module, I use the following connection strings:
<!-- Connection String for SQL Server 2005 Express
<add
name="SiteSqlServer"
connectionString="Data Source=.\SQLExpress;Integrated Security=True;User Instance=True;AttachDBFilename=|DataDirectory|Database.mdf;"
providerName="System.Data.SqlClient" />
-->
<!-- Connection String for SQL Server 2000/2005 -->
<add name="SiteSqlServer" connectionString="Server=MyCroft;Database=DNN441s;Integrated Security=True;" providerName="System.Data.SqlClient"/>
</connectionStrings>
<appSettings>
<!-- Connection String for SQL Server 2005 Express - kept for backwards compatability - legacy modules <add key="SiteSqlServer" value="Data Source=.\SQLExpress;Integrated Security=True;User Instance=True;AttachDBFilename=|DataDirectory|Database.mdf;"/>
-->
<!-- Connection String for SQL Server 2000/2005 - kept for backwards compatability - legacy modules -->
<add key="SiteSqlServer" value="Server=MyCroft;Database=DNN441s;Integrated Security=True;"/>
You can see I've commented out the connection info for SQL Server 2005 Express, and I have 2 active connection strings, 1 for SQL Server 2005, and another SQL Server 2000/2005 legacy modules.
Once you make that change it should be working. That resosolved the issue for me.
Cheers,
iwonder