jenkinsci/puppet-jenkins — pull request #94 by KlavsKlavsen (2014-02-13 12:05:57+00:00)
Title: Setting jenkins::params defaults to strings instead of bools, since str2...

...bool is used on these settings to convert to bools. So it complains when you give it bools :)
str2bool(): Requires either string to work with at /home/klavs/puppet/modules/jenkins/manifests/init.pp:83

This error is what you get when you just: include jenkins in puppet 3.4.2 atleast.

Perhaps str2bool usage should just be removed - but this solutions seems more backwards compatible.