I have been successfully downloading files for the last few days with no problems, but every once in awhile and now all the time, the "sharing files" dot is red indicating no files are being shared, when I initiate a search in one of the fields the "search" button will not become active, and at the top of the window it indicates "LimeWire: Running the Gnutella Network (Disconnected/no files available.)

What am I doing wrong?

There are any number of reasons your connections can break. Sometimes there seems to be a kind of traffic surge. I notice my uploaders all disappear and most of my connections break. If you have not allowed enough of your bandwidth for your connections and your upload slots are full, you can disconnect from the network.

LW will eventually reconnect on its own, but it can take some time. If you have no downloads going, quit the program and immediately restart.