Hi Gnutellians...
I can confirm that copying a new gnutella.net file worked in my case. The file location in OS x 10.5.1 is Users>(user-name)>Preferences>Limewire.

We upgraded from Windows XP to a new MacBook with OS x 10.5.1. Limewire had been working for a long time - but no joy on the MacBook. I copied the gnutella.net file from our old XP machine to the MacBook and things worked right away. I noticed that the gnutella.net file on the MacBook was an empty - zero-length - file. Looks like something in the current Limewire download can't handle that empty file.

Limewire administrators -(IMHO) I suggest this should be the first thing to try for this problem, since it is a pretty benign change and only applies to gnutella/limewire. Other fixes suggested here - deleting Java runtimes, changing router configurations - are more risky and can adversely impact other applications.