Please check to see if you have S.E.F. (Search Engine Friendly) links enabled and configured properly as this mostly likely is the source of the error. You may ensure it is enabled and configured properly with the following steps:
- In your FTP program, rename the file “htaccess.txt” to “.htaccess”.
- Refresh and check your site. If the problem persists, please consult your hosting provider and make an inquiry for the correct .htaccess file to be put on your server. Alternatively, you may disable S.E.F. links in the Joomla administration panel under the Global Configuration options.