Glad you are enjoying the book. Most chapters convert to 3.1 without incident, however the Chapters that require either the sound project (from Chapter 7) or the SkyboxPipeline (from Chapter 8) need a little more work.
For sound, folks should look here:
For this issue (with the SkyboxPipeline) here are the steps to get everything working for 3.1.
1. Open Chapter 8's SkyboxPipeline solution.
2. Remove the references to the following 3.0 assemblies:
3. Now, re-add those same assemblies, but make sure you select the 3.1 versions.
4. Compile the solution.
At this point Chapter 8 has the updated code and the compiled assembly should be used instead of the one already in the main folder of the chapter (Chapter 29 in this case).
Once the SkyboxPipeline.dll file has been replaced with the newly created one from Chapter 8's bin folder you can upgrade the project like normal.
Hope this helps, if not please let me know.