Your ASP.NET project is not setup for debugging.
- Open up the project’s properties window and set the “Enable ASP.NET Debugging” option.
- Open up your web.config file and make sure the Compilation tag’s debug attribute is set to true.
<compilation defaultLanguage="vb" debug="true" />
Make sure the account you are logged in as and the ASP.NET Worker process is in the local “Debugger Users” group.