Zlib buffer error on gem install

if gem update –system not works and rename ruby/bin/zlib1.dll to zlib.dll not helps try: Open file RUBY_DIRlibrubysite_ruby1.8rubygems.rb And replace existed def self.gunzip(data) by this: def self.gunzip(data) require ‘stringio’ require ‘zlib’ data = StringIO.new data # Zlib::GzipReader.new(data).read data.read(10) # skip the gzip header zis = Zlib::Inflate.new(-Zlib::MAX_WBITS) is = StringIO.new(zis.inflate(data.read)) end