I finish all the installtion step for redmine and configure apache
sree@sree:/usr/share/redmine$ rails -v Rails 3.2.13 sree@sree:/usr/share/redmine$ ruby -v rub
Try
gem uninstall bundler
and remove all bundler versions what you have.
After this, install bundler again.
gem install bundler -v 1.0.21
I hope this works to you.