Use your debugger and look at the error console.
Chrome debugger, for example, shows these errors:
not found: resource://jid1-ryetb1dajacauw-at-jetpack-paypal_wishlist_and_notifier-data/stylesheets/notifications.css
Uncaught TypeError: Object [object Object] has no method 'slideshow' widgetkit-5bdb987f.js:14
So your "notifications.css" does not exist, so far as the browser can find it.
And you have an error in the JS code, as noted. No idea why the JS error. You will probably have to ask the widgetkit people.