I am seeing the same problem as the OP. When I enter a search, the search results box on the upper right just goes grey, meaning it is just blank. No search tab, no search results box, just blank. No indication it is searching or that anything is wrong.
However, some unfinished downloads are still in the download box (lower right), and seem to be active (ie I can right-click and search for more sources, etc).

I am using WinXP Home ed, Limewire 4.8.1, a Cable internet connection, and I get no error message.

Limewire worked fine until a few days ago. I tried restarting Limewire, rebooting (warm & cold) my computer, even uninstalling & reinstalling Limewire (newly downloaded).

Anyone know what is going on or what I can do to further troubleshoot this?