There're some things you should not play around with, until you really know core inside out and one of those things are the Path constants that can be set in your
Here's how I do it. Note, that it's uncommented, so it doesn't trigger and WP uses its default.
# define( 'WP_CONTENT_DIR_NAME', 'wp-content' );
# define( 'WP_CONTENT_DIR', ABSPATH.WP_CONTENT_DIR_NAME );
# define( 'WP_CONTENT_URL', WP_SITEURL.WP_CONTENT_DIR_NAME );
There're dozens of things you shouldn't touch in there, but Path constants and the Proxy settings are those that can get broken most easily. WP uses for nearly everything a default and you should simply let it do its job. Aside from having nothing from a dir name change (maybe security through obscurity) it will let a lot of plugins break that don't consider those things.