I had similar errors so I downloaded the js from http://jqueryui.com/themeroller/themeswitchertool/, saved it as jquery.themeswitcher.js and replaced all http jquery-ui urls with google apis https urls.
The only changes were in the var switcherpane where each link looks like:
<li><a href=
"http://jqueryui.com/themeroller/css/parseTheme.css.php?....">
<img src=
"http://jqueryui.com/themeroller/images/themeGallery/theme_90_ui_dark.png" alt=
"UI Darkness" title="UI Darkness" /> <span class="themeName">UI
darkness</span></a></li>
Which I replaced with:
<li><a href="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.23/themes/ui-lightness/jquery-ui.css">
<img src="content/images/theme_90_ui_light.png" alt="UI Lightness" title=
"UI Lightness" /><span class="themeName">UI lightness</span></a></li>
If you search through the file there are a few other html images that are referenced further down.
You can find all the images here