Downloading the new version of gnutella.net to my Desktop did the trick! I had been suffering with the same problem as everyone mentioned: LimeWire Pro 4.16.6 worked for quite awhile and then just seemed to quit. After copying the current version of gnutella.net, all is working well again. Thanks for the tip!

What's strange, however, is that on my laptop running LimeWire Pro 4.14.10 with same router/modem as my desktop, I don't have the problem at all. Computers: can't live with 'em, can't live without 'em.