That's the source code package for your kernel. It may be on the install CDs, else you *should* be able to download it from a urpmi source. But that seems to be the problem that you're having. If it's showing up on your urpmi download list and you don't want it to show up anymore, check this link
You may also be having trouble with the specific location that you're using as a urpmi source. For example, I use the UTK servers, but they are unavailable during school hours, so I receive error messages whenver I try to pull any packages during those hours.