Alright I am assuming, based on the error message you provided, that you are woring with chapter 28. (The error specifically said: 'c:\ProCsharp\Chapter28\PCSWebClient1') Problem is, I can not recreate your problem *IF* I follow the readme files.
For example, if i try to directly open the .sln file from the Archive Visual Studio barks that: "...the project file or web has been moved, renamed or is not on this computer."
Now, if i got into my C drive and create a folder named ProCSharp and then inside of that folder create a folder named Chapter28 and then copy all of the example directories to the C:\ProCSharp\Chapter28 location, this corrects the problem.
So your directory tree for C:\ProCSharp\Chapter28 looks like this:
I tested this in Full blown Visual Studio 2005, 2008 Beta 2, and Visual Web Developer 2005. Can you provide me with any other information?
Read this if you want to know how to get a correct reply for your question:
Technical Editor for:
Beginning Visual C# 2008
Professional Search Engine Optimization with ASP.NET
Professional IIS 7 and ASP.NET Integrated Programming
Wrox Blox: Introduction to Google Gears
Wrox Blox: Create Amazing Custom User Interfaces with WPF and .NET 3.0