RGB theme sidebar problem since WP 2.8

The sidebar of the RGB theme is supposed to be tabbed.
Now the tabs are just one list down, no tabs.
https://www.streamconsult.nl/ – sidebar on the right
Here you can see how it is supposed to work https://xuyiyang.com/wordpress-themes/rgb/

I guess it has something to do with this – I did not change anything in theme and before it worked

jQuery(function() {
jQuery(‘#sidebar > ul#ui-tabs’).tabs({ fx: { opacity: ‘toggle’ } });
});

Working with Firefox 3.5.2