Ultrapeers act as "hubs," maintaining connections to many leaf nodes (as well as other ultrapeers) and relaying queries and results as appropriate. This can be an intensive operation, so you might not even want to be an ultrapeer due to bandwidth concerns. You may also notice that serving as an ultrapeer uses more processor time.

There's no way (none that I'm aware of from within LimeWire, anyway) to force the client to serve as an ultrapeer, but there is a way to disable the ultrapeer capability if it's undesirable. This setting is located in the Preferences.

Depending on a number of factors, you may find that you get better results while only connected as a leaf.

You can get more information on your connections by looking at the Connections tab. If it's not visible, select Connections from the View menu. At the bottom of this tab, it will say either "Ultrapeer" or "Leaf," the list displays the other clients you are connected to.

As for the sharing, be sure you give LimeWire enough time to find all of the files. It scans all of the shared files and does not add a file until it has been checksummed. This information is usually cached on-disk so that LimeWire can share files more quickly when it is launched, but if the cache moves (it has a few times in recent memory) or becomes truncated or corrupt (again, it's happened), LimeWire may need to rescan. Large files can take a long time to checksum.

Mark