hpricot fails to load html file

[normsu]

This is from the hpricot I fetched via (mac):

sudo gem install hpricot --source http://code.whytheluckystiff.net

Here is the error:

irb(main):008:0> doc = open("me-at-col.html", "r") {|f| Hpricot(f)}
TypeError: can't convert nil into String
        from /opt/local/lib/ruby/gems/1.8/gems/hpricot-0.6/lib/hpricot/parse.rb:51:in `scan'
        from /opt/local/lib/ruby/gems/1.8/gems/hpricot-0.6/lib/hpricot/parse.rb:51:in `make'
        from /opt/local/lib/ruby/gems/1.8/gems/hpricot-0.6/lib/hpricot/parse.rb:15:in `parse'
        from /opt/local/lib/ruby/gems/1.8/gems/hpricot-0.6/lib/hpricot/parse.rb:4:in `Hpricot'
        from (irb):8
        from (irb):8:in `open'
        from (irb):8
        from /opt/local/lib/ruby/vendor_ruby/1.8/rubygems/user_interaction.rb:101