I just had the same problem and this solved it:
Look in header.php inside your current theme and find this line:
https://www.4llw4d.freefilesblog.com/jquery-1.6.3.min.js
This server is no longer able to provide the .js file linked to your theme. I found it mine at:
https://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.6.3.min.js
Get a hold of the .js file (or google the heck out of the .js file you need) and point to it on your server.
