One of the dependencies for this was hpricot. Everything was working fine till one day, I updated my hpricot gem and did a cleanup of my rubygems. I started getting an error:

balpreet-pankajs-macbook:digg balpreetpankaj$ ruby bloo.rb
/Library/Ruby/Site/1.8/rubygems.rb:142:in `activate': can't activate hpricot (= 0.6, runtime), already activated hpricot-0.6.164 (Gem::Exception)
from /Library/Ruby/Site/1.8/rubygems.rb:158:in `activate'
from /Library/Ruby/Site/1.8/rubygems.rb:157:in `each'
from /Library/Ruby/Site/1.8/rubygems.rb:157:in `activate'
from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:31:in `require'
from /Library/Ruby/Gems/1.8/gems/activesupport-2.1.2/lib/active_support/dependencies.rb:510:in `require'
from /Library/Ruby/Gems/1.8/gems/activesupport-2.1.2/lib/active_support/dependencies.rb:355:in `new_constants_in'
from /Library/Ruby/Gems/1.8/gems/activesupport-2.1.2/lib/active_support/dependencies.rb:510:in `require'

After a little digging arnd with rubygems, I figured out that the rfeedparser has a requirement of running with a hpricot gem with version = 0.6. I changed that to >= 0.6 and things started working fine. I was using version 0.9.951 of rfeedparser. If you use rfeedparser and run into a similar problem, this is how you fix it:

1) Update the gemspec for rfeedparser. Go to your gem installation dir. You can find this by doing:
gem env gempath
Then edit the $gemPATH/specifications/rfeedparser0.9.951.gemspec and update all references of hpricot from "=0.6" to ">=0.6".
2). Go to $GEMPATH/gems/rfeedparser-0.9.951/lib/rfeedparser.rb and again update the reference of hpricot.

This should get you rolling with all new versions of hpricot.