There's been a bit of an issue with Catalyst's usage of YAML as a default config file format. This is mostly due to some problems introduced in the latest YAML distro.
In the end, core YAML support was removed. My latest plugin Catalyst::Plugin::ConfigLoader will fill the void created by this change. Currently it loads five different file formats:
Usage is simple; add it to the beginning of your plugin list:
use Catalyst qw( ConfigLoader ... );
Comments welcome!