They can all be that way. There are more people trying to download files than there are sharing files. Most people who share files have a lot of people trying to get those files.

Keep trying - you will eventually find a host that has a free upload slot and be able to download some files.

If you are not sharing files yourself this may contribute to your problems - LimeWire incorporates an anti-freeloader feature. I have it enabled - download requests from clients that are not sharing themselves are refused.

Mark