At the start of December 2011 Arduino 1.0 was released. This changed a few things, that have caused the sketches for Projects 10, 27 and 28 in this book not to work.
To fix this, you will need to get the latest versions of the Keypad and IRRemote libraries.
The Keypad library can be downloaded from here: http://www.arduino.cc/playground/Code/Keypad
And a mended version of the IRRemote library can be downloaded from the download page on this site.