need further explanation of “no symbols have been

I have seen the posts on this site about the following error: The breakpoint will not currently be hit. No symbols have been loaded for this document.

But, the problem descriptions and solutions haven't addressed the situation I am experiencing so, I hope to get some clarification.

I am using Visual Studio 2010, and working on a very large, somewhat old ASP.NET web application that targets .NET v2. The first page of the application is Login.aspx. If I put a break point on the first line of code within the Page_Load event of the Login.aspx page. I get the yellowed-out warning icon on the break point, with the message above. If, while in debug mode, I go to Debug >> Windows >> Modules, I see that App_Web_login.aspx.cdcab7d2.DLL has a Symbol Status that reads "No symbols loaded". The Path for the symbols is like this: C:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files...\App_Web_login.aspx.cdcab7d2.DLL. I have checked that path, and a DLL file does exist there. So, if I right-click on this listing in the Modules page, and select "Load symbols from " and "Symbols Path", I get a dialog box, pointing to the path I just listed but, it is asking for a .pdb file! There is no .pdb file in that directory. Actually there is no App_Web_login.aspx.cdcab7d2.pdb file anywhere on my machine.

Also, there is an App_Web_login.aspx.cdcab7d2.DLL file located in the bin folder of my project. I was hoping that Visual Studio would generate a new .dll file there if I rebuilt the project. But, if I remove that .dll file, the project won't build.

Very confusing.

How can I get the symbols file situation straightened out?

Thanks, in advance, for any help you can provide.

Special Note: Here is what is listed in the element of the web.config file:

        <compilation defaultLanguage="vb" debug="true">
        <compilers>
            <compiler language="vb" type="Microsoft.VisualBasic.VBCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" extension=".VB" compilerOptions="/define:Debug=True /define:Trace=True /imports:Microsoft.VisualBasic,System,System.Collections,System.Configuration,System.Data,System.Drawing,System.Web,System.Web.UI,System.Web.UI.HtmlControls,System.Web.UI.WebControls"/>
        </compilers>
        <assemblies>...

Thanks again for any help...