From: "Peña, Botp" <botp@...>
Date: 2008-09-11T18:41:25+09:00
Subject: Re: How to check if a webpage exists

From: Davide Benini [mailto:nutsmuggler@hotmail.com] 
# > try
# > 
# > # require 'open-uri'
# > #  begin
# > #    open "www.does.not.exist.sdadasdas.com", :proxy=>true
# > 
# > replace the above line with
# > 
# >     puts open("www.does.not.exist.sdadasdas.com",:proxy=>true).read
# > 
# > post the output again
# > 
# > #    p "i'm ok"   #<-- ok codes here
# > #  rescue => e
# > #   p "sorry can't do"
# > #   p "error is: #{e}"
# > # end
# 
# The output is
# 
# "sorry can't do"
# "error is: can't convert Hash into String"
# 
# So now there is type conflict...

because i just copied your url.
try this,

  puts open("http://www.does.not.exist.sdadasdas.com",:proxy=>true).read