Frontend login error: You cannot access the private section

A database snippet for Joomla.

Login into your database and run this snippet on the ASSETS table:

UPDATE `prefix_assets` SET `parent_id`=1 WHERE `parent_id`=0 AND id>1

Replace prefix_ with your relevant table prefix, this was traditionally jos_ in Joomla 1.5 and will likely be something quite different in Joomla 2.5.x and 3.1.x