Need more Sources mean it looking for more sources, well, hard to explain it. Your canditate possiblity ignored you or busy. So LimeWire is working on other host who have the same files as you looking for.

Most of the time, just search again for that file, the same excat word from that title and put it in on the search then search it, when that file appear on the result, the LimeWire should start connecting the host. but if it still need more source, then possible the host is ignoring you. it happens to everyone

I know "Need more sources" is really getting on your nerves