A PHP Error was encountered

Severity: Notice

Message: Trying to get property of non-object

Filename: controllers/Categories.php

Line Number: 30

Backtrace:

File: /home/roxoqdat/code-love.tk/demoblog/application/controllers/Categories.php
Line: 30
Function: _error_handler

File: /home/roxoqdat/code-love.tk/demoblog/index.php
Line: 315
Function: require_once