If you get an error that looks like this on the front end of your Magento installation – at the top of the page:
Fatal error: spl_autoload() [<a href=’function.spl-autoload’>function.spl-autoload</a>]: Class Zend_Log could not be loaded in /home/corporat/public_html/app/code/core/Mage/Core/functions.php on line 247
Don’t panic, it’s just a session / disk quota issue…
The solution is to simply navigate to your session folder located here: public_html/var/session/ with an FTP client and delete all the session files found in there. Sorted.