(First in a series of some finite positive number, for the greater edification of Googlers everywhere.)
If you get an error of err: Could not retrieve catalog: Could not parse for environment development: Syntax error at 'Debian' at /etc/puppet/master/manifests/os/Debian.pp:1 on a Debian.pp that only has one line of class Debian {}, just go ahead and change it to class debian {}, then go on with your life. Yes, I know you tried to be smart and use the output of facter operatingsystem and to make include $operatingsystem work right, but just lowercase the class name.
Carry on.