Troubleshooting XML DOM in PHP

DOM.If you have php5 and apache2 installed and DOM is enabled according to phpinfo, but you get following error when you use domxml_open_file($file), I get following error

Fatal error: Call to undefined function domxml_open_file() in …

This is due to domxml_open_file is DOM XML function. DOM XML is now moved to the PECL repository and no longer shipped with PHP 5. If you need DOM functions, you need to use DOM.