To parse the XML files that contain the RSS feeds, XML_RSS requires that the package XML_Parser is installed. However this dependency will be automatically handled by the installer during the installation phase of XML_RSS.
Since most RSS feeds are located on remote hosts, one has to ensure that the PHP configuration value "allow_url_fopen" is set to "On" before running XML_RSS.
To find out the current value of "allow_url_fopen", one can use the function ini_get(). To set a new value of "allow_url_fopen", you must modify the php.ini configuration file of PHP.