I jailbroke my iPhone 4 a few months back. It's currently firmware version 4.1 and jailbroke it with Greenpoison. Been running great until yesterday when I tried to download a new theme through Cydia.

It threw an error "http:/1.1 404" and it appeared to download the theme but it wasn't in Winterboard or the themes folder. I did a quick search and found this tutorial, which I followed:
Fix Cydia Error: HTTP/1.1 404 Not Found & Error: Cached Failure | Jaxov

Now when I try and add all my sources again I get "Did not find repository". I 100% am getting the urls right.

Pretty much asking for help on this one, thanks