Difficult to say. It could range from security software (e.g. a firewall) on your local machine that blocks the trafiic to software or hardware running on your or your ISP's network.
But are you sure it's not one of the other reasons?
Is there another book that dives deeper into 'Displaying and Updating Data'?
I think Professional ASP.NET 3.5 / 4 has a lot more on this. It depends on what you want to dig deeper into: the presentation, or the underlying data technology.