I've found an error on a page in my Magento application; it always show this message error when I visit it:
Fatal error: Class 'DOMDocument' not found in /home/.../lib/Zend/Feed/Abstract.php on line 95
You need to install the DOM extension. You can do so on Debian / Ubuntu using:
sudo apt-get install php5-dom
And on Centos / Fedora / Red Hat:
yum install php-xml
If you get conflicts between PHP 5 and PHP 5.3 packages, you could try to see if the
php53-xml package exists instead.