alltimelowe on "Custom Post Type function 'create_post_type' not found or invalid function name"

I am modifying an existing starter theme. For organization sake I created "cg-post-types.php" since I plan to create more post types; and I am calling this in my functions.php with this

require_once( 'parts/cg-post-types.php' );

It really seems to me that the plugin I installed (http://wordpress.org/extend/plugins/pronamic-google-maps/) is what caused the problem. I didn't realize it doesn't support wordpress 3.5.1.

Thanks