I was testing some MySQL puppet modules on my Vagrant box earlier this week and one of them required augeas.
I kept running into "Could not find a default provider for augeas", however all the appropriate augeas , augeas-lib and ruby-augeas packages were installed. I inspected the different ruby directories and the files were perfectly in /usr/lib/ruby/site_ruby/1.8 where I expected them.

With all the files seemd to be in the right place, my next option was to strace a small ruby script that included augeas, guess what that showed ..

1. stat64("/opt/ruby/lib/ruby/site_ruby/1.8/augeas.rb", 0xbfd2af1c) = -1 ENOENT (No such file or directory)
2. stat64("/opt/ruby/lib/ruby/site_ruby/1.8/augeas.so", 0xbfd2af1c) = -1 ENOENT (No such file or directory)
3. stat64("/opt/ruby/lib/ruby/site_ruby/1.8/i686-linux/augeas.rb", 0xbfd2af1c) = -1 ENOENT (No such file or directory)
4. …