jos-Error: Invalid controller: name='users', format='opensearch'

JSite -> dispatch() @ /home/vkcame/public_html/joomlasites/vkham/index.php:42
JError :: raiseError() @ /home/vkcame/public_html/joomlasites/vkham/includes/application.php:205
JError :: raise() @ /home/vkcame/public_html/joomlasites/vkham/libraries/joomla/error/error.php:251