Thanks for writing us about this, and I'm sorry for the inconvenience. It looks like the files are not currently available on our site, but we're working on getting the added. I'll let you know when the files are available.
The example files for Introduction Microsoft WebMatrix are now available at http://examples.oreilly.com/9780735649705-files/.
Here's the direct link to download the files.
I'm sorry for the delay in making these available, and thank you for your patience.
Have a great day!