Error on Widgets-Page

Hey!

First of all, thanks for this very awesome theme! I really like the way how to personalize the theme via the widgets.
Since a couple of days the page Design->Widgets is broken. I guess it is an jQuery error or something? Unfortunately I can’t really interpret the error message well… e. g. when I load the Widget-page, I get this message:

Consider using ‘dppx’ units, as in CSS ‘dpi’ means dots-per-CSS-inch, not dots-per-physical-inch, so does not correspond to the actual ‘dpi’ of a screen. In media query expression: print, not all, (-webkit-min-device-pixel-ratio: 1.25), (min-resolution: 120dpi)
in
widgets.php:1

and the following error message, when I click on a Widget:

Uncaught TypeError: Cannot read property ‘open’ of undefined
in
load-scripts.php?c=1&load%5B%5D=hoverIntent,common,admin-bar,media,wp-ajax-response,shortcode,media…:4

I don’t really know, but since I also can’t drag and drop the Widgets anymore, I guess that it is a jQuery error?

Hope that someone can help me.

Thanks in advance and have a nice day! =)
Eric