Puppet stdlib module file_line doesn't have an effect

Question

I have the following module:

include stdlib
class pulseaudio-zeroconf {
        package { "pulseaudio-module-zeroconf":
                ensure => installed
        }

        file_line { "pulseaudiozeroconfdiscoverentry":
                path => "/etc/pulse/default.pa",
                line => "load-module module-zeroconf-discover",
                ensure => present,
        }
}

The package pulseaudio-module-zeroconf is installed but somehow file_line has no effect on /etc/pulse/default.pa.

We know for sure that the module is executed: If we introduce an error to the module, puppet throws an error.

OS: Ubuntu 12.04 with Puppet 2.7.11

Puppetmaster: Debian Squeeze with Puppet 2.7.17 and stdlib 2.3.2 (we tested several versions)

Answer 1

We managed to solve this issue by enabling pluginsync in the puppet config on the puppethosts.

#puppethost:/etc/puppet/puppet.conf 
[main]
#...
pluginsync=true