Help!!! Http 500 error

Question

My magento site suddenly stopped opening and is throwing an http 500 error. After activating diplay errors in my index.php file the site shows:

Fatal error: Class 'Mage_Core_Model_Session_Abstract' not found in /var/www/html/app/code/core/Mage/Core/Model/Session/Abstract/Varien.php on line 35

How can i solve this problem?

Answer 1

Change settings in your httpd.conf file from Allow Override none to Allow Override all