rails 3.1, Installing capybara-webkit, Failed to build gem native extension, what to do?

Question

I am trying to install capybara-webkit (0.8.0), but I get the error below, can any body help, I am on ubuntu 11.10.

Installing capybara-webkit (0.8.0) with native extensions Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

    /home/sam/.rvm/rubies/ruby-1.9.3-p0/bin/ruby extconf.rb  /usr/bin/qmake /usr/bin/make cd src/ && /usr/bin/qmake

/home/sam/Documents/RoR/course_builder/CDPATH=/ruby/1.9.1/gems/capybara-webkit-0.8.0/src/webkit_server.pro -spec /usr/share/qt4/mkspecs/linux-g++ -o Makefile.webkit_server /usr/bin/make cd src/ && make -f Makefile.webkit_server make[1]: Entering directory /home/sam/Documents/RoR/course_builder/CDPATH=/ruby/1.9.1/gems/capybara-webkit-0.8.0/src' g++ -c -pipe -O2 -Wall -W -D_REENTRANT -DQT_WEBKIT -DQT_NO_DEBUG -DQT_WEBKIT_LIB -DQT_GUI_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtNetwork -I/usr/include/qt4/QtGui -I/usr/include/qt4/QtWebKit -I/usr/include/qt4 -I. -o RequestedUrl.o RequestedUrl.cpp make[1]: g++: Command not found make[1]: *** [RequestedUrl.o] Error 127 make[1]: Leaving directory /home/sam/Documents/RoR/course_builder/CDPATH=/ruby/1.9.1/gems/capybara-webkit-0.8.0/src' make: * [sub-src-webkit_server-pro-make_default-ordered] Error 2

make cd src/ && make -f Makefile.webkit_server make[1]: Entering directory /home/sam/Documents/RoR/course_builder/CDPATH=/ruby/1.9.1/gems/capybara-webkit-0.8.0/src' g++ -c -pipe -O2 -Wall -W -D_REENTRANT -DQT_WEBKIT -DQT_NO_DEBUG -DQT_WEBKIT_LIB -DQT_GUI_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtNetwork -I/usr/include/qt4/QtGui -I/usr/include/qt4/QtWebKit -I/usr/include/qt4 -I. -o RequestedUrl.o RequestedUrl.cpp make[1]: g++: Command not found make[1]: *** [RequestedUrl.o] Error 127 make[1]: Leaving directory /home/sam/Documents/RoR/course_builder/CDPATH=/ruby/1.9.1/gems/capybara-webkit-0.8.0/src' make: * [sub-src-webkit_server-pro-make_default-ordered] Error 2

Gem files will remain installed in /home/sam/Documents/RoR/course_builder/CDPATH=/ruby/1.9.1/gems/capybara-webkit-0.8.0 for inspection. Results logged to /home/sam/Documents/RoR/course_builder/CDPATH=/ruby/1.9.1/gems/capybara-webkit-0.8.0/./gem_make.out An error occured while installing capybara-webkit (0.8.0), and Bundler cannot continue. Make sure that gem install capybara-webkit -v '0.8.0' succeeds before bundling.