As @eckostylez clearly said but sorta dumbed down.. the page loads over HTTPS while the files are trying to load over HTTP, website doesn't wanna use any insecure files so change the links in your head tags. In the spoiler help it clearly shows what you've done wrong although I'd try fixing it...
I would say C# is my favourite although recently I've been shifting away from C# and getting more into PHP. Maybe using C# in college and not PHP will change my mind but as of now, PHP is my favourite.
Well after a lifetime of learning C# through reading books and trial and error I've became quite the professional with C#. I'm finally happy with my skills with it and I've been able to make the below; hopefully you'll be able to create something as impressive!:)
You won't learn anything from having someone else do it for you - I'll give you the query; feel free to private message me if you're still struggling.
"UPDATE `users` SET `username`='" + Params[1] + "' WHERE `username`='" + TargetUser.Username + "'"
Run that query through the IQuery Adapter.