See Also

I stumbled on this error using VS2005 SP1. The reason for not being able to debug was the below debug setting in my web.config was set to false , make sure it is set to true .

   <system.web>
     <!--  DYNAMIC DEBUG COMPILATION
           Set compilation debug="true" to insert debugging symbols (.pdb information)
           into the compiled page. Because this creates a larger file that executes
           more slowly, you should set this value to true only when debugging and to
           false at all other times.
   -->
     <compilation defaultLanguage="c#" debug="true" />

If all else fails, try disabling SSL. It's not optimal, but it worked for me. (I only disabled SSL on an internal-only development server, not the production server.)

verify the project file (ex: abc.csproj)
go to tag <IISUrl>http://localhost/web20</IISUrl> and make sure your url app the same this.
regards

SYMPTOMS

• An error box appears with the following message, when running a Web application from within Visual Studio 2005:
  Unable to start debugging on the web server. The web server is not configured correctly. See help for common configuration errors. Running the web page outside of the debugger may provide further information.
  
  - or -
  
  
• An error Web page appears with the following message, when attempting to browse directly to a Web application:
  Failed to access IIS metabase

CAUSE

This issue started when I began using the .NET Framework 2.0 and Visual Studio 2005, in conjunction with IIS 6. Anytime I installed/updated IIS after the .NET Framework was already installed, I got the previously mentioned errors.

SOLUTION

NOTE: This is written for inexperienced developers, so please bear with the overly simplified description.

1. Open an instance of the VS Command Prompt (in XP, Start > All Programs > Microsoft Visual Studio 2005 > Visual Studio Tools > Visual Studio 2005 Command Prompt).
2. Change the location to your current .NET Framework directory by entering cd C:\WINDOWS\Microsoft.NET\Framework\vX.X.xxxxx and pressing <ENTER> (where the x's represent the version of the .NET Framework you have installed).
3. Type aspnet_regiis -i and press <ENTER>.

The command prompt will show that some work is being done. Once it has completed, the problem should be fixed.

-----------------------------------------------Even the above doesn't work---------------------------------------------------------------------------------------------

what should be done., I use windows server 2003 R2 Standard edition / VS 2005 Team. / Do please help

not sure what fixed mine but it didn't take effect until I did an IISReset. so please do IISReset more often!