After completing Joomla 1.5 installation process, we usually going to the Joomla administrator page. But when I go to an administrator page joomla 1.5, page load very slow, and after it finish loading page, there is an error message "Error loading feed data". In this installation process, i also installing Joomla 1.5 sample data. After googling for a while, i found how to repair these errors. Here are the steps:
1. Go to page administrator
2. Go to Extensions, then click on the module manager
3. Then select the pages / tabs administrator
4. Find a module "Joomla! Security Newsfeed"
5. Then disable the module
Finally, logout of the administrator page and return to log in to the page, then we will not see the error message again.
Thanks.
Source : http://kampiabareh.blogspot.com/2010/09/how-to-repair-error-loading-feed-data.html