Visual Studio 2010 will throw an error when debugging if the LMHOSTS file is not setup correctly. The error is "Internet Explorer cannot display the webpage". To correct, you need to update the LMHOSTS file.
To updated the LMHOSTS file,
From the Start Memo, click on "All Programs", "Accessories" and right clilck on "Notepad" and select "Run as Administrator".
Add an entry to the LMHOSTS file:
"127.0.0.1 localhost"
That should be it.