Puppet is very particular about the Ruby version on Windows. While 2.2 and 2.3 versions of Ruby are available, puppet only runs without complaint on Ruby 2.1 on my Windows 7 box.
As of May 2016, I installed ruby 2.1.8 and puppet-agent 3.8.7. I also had to install some gems to make puppet-agent happy.
gem install win32-security win32-dir require win32-process top win32-service
Here are the links to downloads for puppet-agent and ruby:
No issues if the right version of ruby and the right gems.