(undefined method `first' for nil:NilClass ) when there is no top_content_candidate

[moustafasamir]

When I tried to get images in this website I got this exception
http://verkoren.wordpress.com/2013/04/12/you-cant-skate-you-old/

<NoMethodError: undefined method `first' for nil:NilClass>

/app/vendor/pismo/pismo/reader/tree.rb:149:in content_at' /app/vendor/pismo/pismo/images/image_extractor.rb:28:ininitialize'
/app/vendor/pismo/pismo/internal_attributes.rb:181:in new' /app/vendor/pismo/pismo/internal_attributes.rb:181:inimages'