If you move your website from development stage to a live version to new server, lets say from local host or other test server the chances that you will get error 500 are higher. You may encounter this issue especially when accessing K2 or user management component in Joomla! administrator panel.

JAdministrator->dispatch() /path-to-your-website/administrator/index.php:46
JError::raiseError() /path-to-your-website/administrator/includes/application.php:164
JError::raise() /path-to-your-website/libraries/joomla/error/error.php:251

The cause of that and solution are pretty straightforward. To fix the problem you need to correct your ‘tmp’ and ‘log’ paths in your configuration file. Those are located in your websites root location /tmp and /logs. To update paths to log folder navigate to Site -> Global Configuration -> System Tab -> and put correct path to your log folder.

To correct path to Temp Folder go to Server tab and fill out correctly field ‘Path to Temp Folder’ in ‘Server Settings’ fieldset.
Once you save configuration problem should be solved.