Before I create a new web application in Visual Studio .NET 2003, I usually create a new website in IIS MMC, then create the new web application based on the url of teh website I created early.
Today, doing the same process as above generated the following error:
The web server reported the following error when attempting to create or open the Web Project located at the following URL: '....' . 'HTTP/1.1 403 Forbidden'
If you ever face such a problem, make sure in the website's properties screen in IIS MMC, in the Home Directory Tab, Execute Permissions is 'Script Only', since by default it will be 'None'.