these repositories are different servers that have different goodies.
here's the down n dirty on how to add em:
go to manage in cydia...the button is on the bottom
click sources then edit then add...
type in the address exactly then add
you might get a warning on copyright blah blah blah...click ok... the repo's still have some legit and free stuff, just may have some cracked stuff too...you can decide later if you want to get cracked or buy
sinful is still up and running...one of my favorites. I think the errors are common. I get them all the time but the repo still loads. check your sources after you load one and it'll be there. The errors might just be that some portions of the repository aren't valid or something???