Thanks in advance to anyone willing to help!

Everything went fine until I got to page 30, Installing SQLite Database Interface for Ruby. Instead of the text shown in the book, this appeared:

Building native extensions. This could take a while...
ERROR: Error installing sqlite3-ruby:
ERROR: Failed to build gem native extension.

/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb install sqlite3-ruby
checking for fdatasync() in -lrt... no
checking for sqlite3.h... yes
checking for sqlite3_open() in -lsqlite3... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.

Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
--with-sqlite3-dir
--without-sqlite3-dir
--with-sqlite3-include
--without-sqlite3-include=${sqlite3-dir}/include
--with-sqlite3-lib
--without-sqlite3-lib=${sqlite3-dir}/lib
--with-rtlib
--without-rtlib
--with-sqlite3lib
--without-sqlite3lib


Gem files will remain installed in /Library/Ruby/Gems/1.8/gems/sqlite3-ruby-1.2.2 for inspection.
Results logged to /Library/Ruby/Gems/1.8/gems/sqlite3-ruby-1.2.2/ext/sqlite3_api/gem_make.out
Macintosh-2:sqlite-3.5.4 mlapeter$ sudo gem install sqlite3-ruby
Building native extensions. This could take a while...
ERROR: Error installing sqlite3-ruby:
ERROR: Failed to build gem native extension.

/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb install sqlite3-ruby
checking for fdatasync() in -lrt... no
checking for sqlite3.h... yes
checking for sqlite3_open() in -lsqlite3... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.

Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
--with-sqlite3-dir
--without-sqlite3-dir
--with-sqlite3-include
--without-sqlite3-include=${sqlite3-dir}/include
--with-sqlite3-lib
--without-sqlite3-lib=${sqlite3-dir}/lib
--with-rtlib
--without-rtlib
--with-sqlite3lib
--without-sqlite3lib


Gem files will remain installed in /Library/Ruby/Gems/1.8/gems/sqlite3-ruby-1.2.2 for inspection.
Results logged to /Library/Ruby/Gems/1.8/gems/sqlite3-ruby-1.2.2/ext/sqlite3_api/gem_make.out