jos-Error: JHtml: :jquery nicht unterst├╝tzt. Datei nicht gefunden.

JSite -> render() @ /homepages/28/d439602543/htdocs/joomla/index.php:48
JDocumentHTML -> parse() @ /homepages/28/d439602543/htdocs/joomla/includes/application.php:259
JDocumentHTML -> _fetchTemplate() @ /homepages/28/d439602543/htdocs/joomla/libraries/joomla/document/html/html.php:414
JDocumentHTML -> _loadTemplate() @ /homepages/28/d439602543/htdocs/joomla/libraries/joomla/document/html/html.php:591
require() @ /homepages/28/d439602543/htdocs/joomla/libraries/joomla/document/html/html.php:531
include_once() @ /homepages/28/d439602543/htdocs/joomla/templates/theme3224/index.php:2
JHtml :: _() @ /homepages/28/d439602543/htdocs/joomla/templates/theme3224/includes/includes.php:4
JError :: raiseError() @ /homepages/28/d439602543/htdocs/joomla/libraries/joomla/html/html.php:123
JError :: raise() @ /homepages/28/d439602543/htdocs/joomla/libraries/joomla/error/error.php:251