If you receive the following, you should check the event log of your server to solve the issue. I once received this because the service account running the website did not have correct access rights. http://msdn.microsoft.com/en-us/library/kwzs111e.aspx

Server Application Unavailable

The web application you are attempting to access on this web server is currently unavailable.  Please hit the "Refresh" button in your web browser to retry your request.

Administrator Note: An error message detailing the cause of this specific request failure can be found in the application event log of the web server. Please review this log entry to discover what caused this error to occur.

Happy Programming!