Hello, Does anybody know how to deal with this gem problem ? Thanks a lot in advance for your help. After trying to run gem update the message is: gem update Updating installed gems Updating hpricot Building native extensions. This could take a while... ERROR: While executing gem ... (Gem::Installer::ExtensionBuildError) ERROR: Failed to build gem native extension. c:/ruby/bin/ruby.exe extconf.rb update checking for stdio.h... no *** extconf.rb failed *** Could not create Makefile due to some reason, probably lack of necessary libraries and/or headers. Check the mkmf.log file for more details. You may need configuration options. BBHoss Provided configuration options: --with-opt-dir --without-opt-dir --with-opt-include --without-opt-include=${opt-dir}/include --with-opt-lib --without-opt-lib=${opt-dir}/lib --with-make-prog --srcdir=. --curdir --ruby=c:/ruby/bin/ruby Gem files will remain installed in c:/ruby/lib/ruby/gems/1.8/gems/hpricot-0.6.161 for inspection. Results logged to c:/ruby/lib/ruby/gems/1.8/gems/hpricot-0.6.161/ext/fast_xs/gem_make.out mkmf.log shows: have_header: checking for stdio.h... -------------------- no "cl -nologo -E -I. -Ic:/ruby/lib/ruby/1.8/i386-mswin32 -I. -MD -Zi -O2b2xg- -G6 conftest.c -P" checked program was: /* begin */ 1: #include <stdio.h> /* end */ -------------------- -- Posted via http://www.ruby-forum.com/.