Error message
Fatal error: Uncaught exception 'PropelException' with message 'Call to undefined method: makeRoot' in /usr/share/php/propel/om/BaseObject.php:325
You need to replace inheritance classes for nested set. In your model class, find and replace.
class Contents extends BaseContents
with this
class Contents extends BaseContentsNestedSet
also find and replace
class ContentsPeer extends BaseContentsPeer
with this
class ContentsPeer extends BaseContentsNestedSetPeer
You are now good to go.
