There is nothing wrong with your code. The error is most probably within your IIS setup or the way you view the page. Are you using Dreamweaver/Frontpage to code, if so you should check your Site definition and setup one more time.
When I started with ASP i experienced the same error, because i 'openend' the file in Exploreer instead of writing the location in the address field. To view a page you must write the following in the address field :
http://YourServerName/YourApplicatio...r/FileName.asp