Greetings!  I have a new installation of DNN 4.3.5 and it seems to work fine.  My problem is adding certain modules to containers.  It isn't every one, but some of them give me the error below and it appears to always be the same error:

A critical error has occurred.
Unable to open the physical file "C:\Inetpub\DotNetNuke\Website\App_Data\Database.mdf". Operating system error 32: "32(The process cannot access the file because it is being used by another process.)". An attempt to attach an auto-named database for file C:\Inetpub\DotNetNuke\Website\App_Data\Database.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share.

Can ANYONE help?  I have included my setup and connection strings in my web.config file in which I have deleted the non-SQL Express statements:

Windows 2003 Server Std
SQL Server 2005 Express
DNN 4.3.5
IE 6.0
ASP.NET 2.0.50727

<connectionStrings>
    <!-- Connection String for SQL Server 2005 Express -->
    <add name="SiteSqlServer" connectionString="Data Source=robinson-c8b57r\SQLExpress;Database=DotNetNuke;User ID=administrator;Password=*******;Connection Timeout=5; Integrated Security=True;User Instance=True;AttachDBFilename=|DataDirectory|Database.mdf;" 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=robinson-c8b57r\SQLExpress;Integrated Security=True;User Instance=True;AttachDBFilename=|DataDirectory|Database.mdf;" />